Yamaha YZF-R125, Service Manual

Page 1: ...5D7 F8197 E0 YAMAHAR125 COM SERVICE MANUAL YZF R125 ...

Page 2: ...trie First edition January 2008 All rights reserved Any reproduction or unauthorized use without the written permission of MBK Industrie is expressly prohibited YamahaR125 COM For more information about Yamaha R125 Login to http www yamahar125 com ...

Page 3: ...ations and sig nificant changes in specifications or procedures will be forwarded to all authorized Yamaha dealers and will appear in future editions of this manual where applicable NOTE Designs and specifications are subject to change without notice EAS20080 IMPORTANT MANUAL INFORMATION Particularly important information is distinguished in this manual by the following The Safety Alert Symbol mea...

Page 4: ...ion titles 2 appear in smaller print than the section title To help identify parts and clarify procedure steps there are exploded diagrams 3 at the start of each removal and disassembly section Numbers 4 are given in the order of the jobs in the exploded diagram A number indicates a disas sembly step Symbols 5 indicate parts to be lubricated or replaced Refer to SYMBOLS A job instruction chart 6 a...

Page 5: ...4 5 6 7 8 1 Serviceable with engine mounted 2 Filling fluid 3 Lubricant 4 Special tool 5 Tightening torque 6 Wear limit clearance 7 Engine speed 8 Electrical data 9 Engine oil 10 Gear oil 11 Molybdenum disulfide oil 12 Brake fluid 13 Wheel bearing grease 14 Lithium soap based grease 15 Molybdenum disulfide grease 16 Silicone grease 17 Apply locking agent LOCTITE 18 Replace the part with a new one ...

Page 6: ...YamahaR125 COM ...

Page 7: ...EAS20110 TABLE OF CONTENTS GENERAL INFORMATION 1 SPECIFICATIONS 2 PERIODIC CHECKS AND ADJUSTMENTS 3 CHASSIS 4 ENGINE 5 COOLING SYSTEM 6 FUEL SYSTEM 7 ELECTRICAL SYSTEM 8 TROUBLESHOOTING 9 YamahaR125 COM ...

Page 8: ...YamahaR125 COM ...

Page 9: ...I SYSTEM 1 2 FI SYSTEM 1 3 MULTI FUNCTION DISPLAY 1 4 IMPORTANT INFORMATION 1 5 PREPARATION FOR REMOVAL AND DISASSEMBLY 1 5 REPLACEMENT PARTS 1 5 GASKETS OIL SEALS AND O RINGS 1 5 LOCK WASHERS PLATES AND COTTER PINS 1 5 BEARINGS AND OIL SEALS 1 6 CIRCLIPS 1 6 CHECKING THE CONNECTIONS 1 7 SPECIAL TOOLS 1 8 YamahaR125 COM ...

Page 10: ...HICLE IDENTIFICATION NUMBER The vehicle identification number 1 is stamped into the right side of the steering head pipe EAS20150 MODEL LABEL The model label 1 is affixed to the frame This information will be needed to order spare parts 1 1 YamahaR125 COM ...

Page 11: ...ine As the requirements for the engine to deliver more performance and cleaner exhaust gases increase it becomes necessary to control the air fuel ratio in a more precise and finely tuned manner To accom modate this need this model has adopted an electronically controlled fuel injection FI system in place of the conventional carburetor system This system can achieve an optimum air fuel ratio requi...

Page 12: ...nd the injection timing are controlled by the ECU Signals that are input from the throttle position sensor crankshaft position sensor intake air pressure sensor intake air temperature sensor lean angle sensor and coolant temperature sensor enable the ECU to determine the injection duration The injection timing is determined through the signals from the crankshaft position sensor As a result the vo...

Page 13: ... Imp gal of fuel remains in the fuel tank the odometer display will automatically change to the fuel reserve tripmeter mode F TRIP and start counting the distance traveled from that point and the last segment of the fuel meter will start flashing In that case pushing the RE SET SELECT button switches the display be tween the various tripmeter and odometer modes in the following order F TRIP TRIP 1...

Page 14: ... installation of all parts 5 Keep all parts away from any source of fire EAS20200 REPLACEMENT PARTS Use only genuine Yamaha parts for all replace ments Use oil and grease recommended by Yamaha for all lubrication jobs Other brands may be similar in function and appearance but inferior in quality EAS20210 GASKETS OIL SEALS AND O RINGS 1 When overhauling the engine replace all gaskets seals and O ri...

Page 15: ...il bearings liberally when installing if appropriate CAUTION ECA13300 Do not spin the bearing with compressed air because this will damage the bearing surfac es EAS20240 CIRCLIPS Before reassembly check all circlips carefully and replace damaged or distorted circlips Al ways replace piston pin clips after one use When installing a circlip 1 make sure the sharp edged corner 2 is positioned opposite...

Page 16: ... 3 Check All connections Loose connection Connect properly NOTE If the pin 1 on the terminal is flattened bend it up 4 Connect Lead Coupler Connector NOTE Make sure all connections are tight 5 Check Continuity with the pocket tester NOTE If there is no continuity clean the terminals When checking the wire harness perform steps 1 to 3 As a quick remedy use a contact revitalizer available at most pa...

Page 17: ...stakes NOTE For U S A and Canada use part number starting with YM YU or ACC For others use part number starting with 90890 Tool name Tool No Illustration Reference pages Pocket tester 90890 03112 Analog pocket tester YU 03112 C 1 7 5 36 8 61 8 62 8 63 8 66 8 67 8 68 8 69 8 70 8 71 8 72 8 73 8 74 8 75 Tappet adjusting tool 90890 01311 Six piece tappet set YM A5970 3 4 FI diagnostic tool 90890 03182...

Page 18: ...90 01326 T handle 3 8 drive 60 cm long YM 01326 4 48 4 49 Fork seal driver weight 90890 01367 Replacement hammer YM A9409 7 4 49 4 50 Fork seal driver attachment ø33 90890 01368 Replacement 33 mm YM A9409 4 4 49 Yamaha bond No 1215 90890 85505 Three Bond No 1215 5 12 5 33 5 60 Tool name Tool No Illustration Reference pages YM 01300 YM A9409 7 YM A5142 4 YamahaR125 COM ...

Page 19: ...YM 04116 5 19 Valve guide installer ø4 5 90890 04117 Valve guide installer 4 5 mm YM 04117 5 19 Valve guide reamer ø4 5 90890 04118 Valve guide reamer 4 5 mm YM 04118 5 19 Piston pin puller set 90890 01304 Piston pin puller YU 01304 5 25 Sheave holder 90890 01701 Primary clutch holder YS 01880 A 5 31 5 32 5 33 Flywheel puller 90890 01362 Heavy duty puller YU 33270 B 5 31 Tool name Tool No Illustra...

Page 20: ...ler gauge set YU 26900 9 5 42 Crankcase separating tool 90890 01135 Crankcase separator YU 01135 B 5 62 Crankshaft installer pot 90890 01274 Installing pot YU 90058 5 63 Crankshaft installer bolt 90890 01275 Bolt YU 90060 5 63 Tool name Tool No Illustration Reference pages YU 90058 YU 90059 YamahaR125 COM ...

Page 21: ...spacer YM 91044 5 63 Radiator cap tester 90890 01325 Radiator pressure tester YU 24460 01 6 3 Radiator cap tester adapter 90890 01352 Radiator pressure tester adapter YU 33984 6 3 Mechanical seal installer 90890 04145 6 8 Tool name Tool No Illustration Reference pages YM 91044 YU 24460 01 YU 33984 YamahaR125 COM ...

Page 22: ... 8 Pressure gauge 90890 03153 YU 03153 7 3 Fuel pressure adapter 90890 03181 7 3 Ignition checker 90890 06754 Opama pet 4000 spark checker YM 34487 8 69 Digital circuit tester 90890 03174 Model 88 Multimeter with tachometer YU A1927 8 73 Tool name Tool No Illustration Reference pages YamahaR125 COM ...

Page 23: ...2 15 GENERAL TIGHTENING TORQUE SPECIFICATIONS 2 15 ENGINE TIGHTENING TORQUES 2 16 CHASSIS TIGHTENING TORQUES 2 19 LUBRICATION POINTS AND LUBRICANT TYPES 2 22 ENGINE 2 22 CHASSIS 2 24 LUBRICATION SYSTEM CHART AND DIAGRAMS 2 25 ENGINE OIL LUBRICATION CHART 2 25 LUBRICATION DIAGRAMS 2 27 COOLING SYSTEM DIAGRAMS 2 31 CABLE ROUTING 2 33 YamahaR125 COM ...

Page 24: ...verall length 2015 mm 79 3 in Overall width 660 mm 26 0 in Overall height 1065 mm 41 9 in Seat height 818 mm 32 2 in Wheelbase 1355 mm 53 3 in Ground clearance 155 mm 6 10 in Minimum turning radius 3100 mm 122 0 in Weight With oil and fuel 138 0 kg 304 lb Maximum load 185 kg 408 lb YamahaR125 COM ...

Page 25: ...ndard MA Engine oil quantity Total amount 1 15 L 1 22 US qt 1 01 Imp qt Without oil filter element replacement 0 95 L 1 00 US qt 0 84 Imp qt With oil filter element replacement 1 00 L 1 06 US qt 0 88 Imp qt Oil filter Oil filter type Paper Oil pump Oil pump type Trochoid Inner rotor to outer rotor tip clearance Less than 0 15 mm 0 0059 in Limit 0 23 mm 0 0091 in Outer rotor to oil pump housing cle...

Page 26: ... 0 500 Spark plug s Manufacturer model NGK CR8E Spark plug gap 0 7 0 8 mm 0 028 0 031 in Cylinder head Volume 9 90 10 50 cm 0 60 0 64 cu in Warpage limit 0 03 mm 0 0012 in Camshaft Drive system Chain drive left Camshaft lobe dimensions Intake A 30 225 30 325 mm 1 1900 1 1939 in Limit 30 125 mm 1 1860 in Intake B 25 127 25 227 mm 0 9893 0 9932 in Limit 25 027 mm 0 9853 in Exhaust A 30 232 30 332 mm...

Page 27: ...n Valve head diameter A exhaust 16 90 17 10 mm 0 6654 0 6732 in Valve face width B intake 1 538 2 138 mm 0 0606 0 0842 in Valve face width B exhaust 1 538 2 138 mm 0 0606 0 0842 in Valve seat width C intake 0 90 1 10 mm 0 0354 0 0433 in Limit 1 6 mm 0 06 in Valve seat width C exhaust 0 90 1 10 mm 0 0354 0 0433 in Limit 1 6 mm 0 06 in Valve margin thickness D intake 0 50 0 90 mm 0 0197 0 0354 in Va...

Page 28: ...exhaust 35 30 mm 1 39 in Spring rate K1 intake 23 54 N mm 134 41 lb in 2 40 kgf mm Spring rate K2 intake 36 58 N mm 208 87 lb in 3 73 kgf mm Spring rate K1 exhaust 23 54 N mm 134 41 lb in 2 40 kgf mm Spring rate K2 exhaust 36 58 N mm 208 87 lb in 3 73 kgf mm Installed compression spring force intake 140 162 N 31 47 36 42 lbf 14 28 16 52 kgf Installed compression spring force exhaust 140 162 N 31 4...

Page 29: ...ons B T 0 80 1 90 mm 0 03 0 07 in End gap installed 0 10 0 25 mm 0 0039 0 0098 in Limit 0 50 mm 0 0197 in Ring side clearance 0 030 0 065 mm 0 0012 0 0026 in Limit 0 100 mm 0 0039 in 2nd ring Ring type Taper Dimensions B T 0 80 2 10 mm 0 03 0 08 in End gap installed 0 10 0 25 mm 0 0039 0 0098 in Limit 0 60 mm 0 0236 in Ring side clearance 0 020 0 055 mm 0 0008 0 0022 in Limit 0 100 mm 0 0039 in Oi...

Page 30: ...ness 2 90 3 10 mm 0 114 0 122 in Wear limit 2 80 mm 0 1102 in Plate quantity 1 pc Clutch plate thickness 1 45 1 75 mm 0 057 0 069 in Plate quantity 4 pcs Warpage limit 0 20 mm 0 0079 in Clutch spring free length 38 71 mm 1 52 in Minimum length 36 77 mm 1 45 in Spring quantity 4 pcs Push rod bending limit 0 500 mm 0 0197 in Transmission Transmission type Constant mesh 6 speed Primary reduction syst...

Page 31: ...odel quantity 1100 87K00 1 Manufacturer AISAN Throttle body Type quantity SE AC28 2 1 Manufacturer MIKUNI ID mark 5D71 00 Fuel injection sensor Crankshaft position sensor resistance 248 372 Ω at 20 C 68 F Intake air pressure sensor output voltage 4 70 5 20 V Intake air temperature sensor resistance 5 7 6 3 kΩ Coolant temperature sensor resistance 2 32 2 59 kΩ at 20 C 68 F 310 326 Ω at 80 C 176 F I...

Page 32: ...m 0 04 in Wheel axle bending limit 0 25 mm 0 01 in Front tire Type Tubeless Size 100 80 17 M C 52H Manufacturer model PIRELLI SPORT DEMON Manufacturer model MICHELIN PILOT SPORTY Wear limit front 1 6 mm 0 06 in Rear tire Type Tubeless Size 130 70 17 M C 62H Manufacturer model PIRELLI SPORT DEMON Manufacturer model MICHELIN PILOT SPORTY Wear limit rear 1 6 mm 0 06 in Tire air pressure measured on c...

Page 33: ...inner 5 5 mm 0 22 in Limit 1 0 mm 0 04 in Brake pad lining thickness outer 5 5 mm 0 22 in Limit 1 0 mm 0 04 in Master cylinder inside diameter 12 7 mm 0 50 in Caliper cylinder inside diameter 32 00 mm 1 1 26 in 1 Recommended fluid DOT 4 Steering Steering bearing type Ball and angular bearing Center to lock angle left 29 5 Center to lock angle right 29 5 Front suspension Type Telescopic fork Spring...

Page 34: ... 162 0 mm 6 38 in Installed length 155 0 mm 6 10 in Spring rate K1 103 00 N mm 588 13 lb in 10 50 kgf mm Spring stroke K1 0 0 54 0 mm 0 00 2 13 in Optional spring available No Swingarm Swingarm end free play limit axial 0 mm 0 in Drive chain Type manufacturer R428HBSOR ROLON Link quantity 131 Drive chain slack 30 0 40 0 mm 1 18 1 57 in 15 link length limit 191 5 mm 7 54 in YamahaR125 COM ...

Page 35: ... 5 0 kΩ AC magneto Model manufacturer F5D7 YAMAHA Standard output 14 0 V 20 8 A 5000 r min Standard output 14 0 V 235 W 5000 r min Stator coil resistance 0 32 0 48 Ω at 20 C 68 F Rectifier regulator Regulator type Semi conductor short circuit Model manufacturer SH650D 11 SHINDENGEN Regulated voltage DC 14 1 14 9 V Rectifier capacity DC 25 0 A Withstand voltage 200 0 V Battery Model 12N5 5 3B YUASA...

Page 36: ... mm 0 65 in Mica undercut depth 1 35 mm 0 05 in Starter relay Model manufacturer 5TN OMROM Amperage 50 0 A Horn Horn type Plane Quantity 1 pc Model manufacturer YF 12 NIKKO Maximum amperage 3 0 A Coil resistance 1 15 1 25 Ω at 20 C 68 F Turn signal relay Relay type Full transistor Model manufacturer FE218BH DENSO Built in self canceling device No Turn signal blinking frequency 75 95 cycles min Wat...

Page 37: ...Running rpm 4800 r min Fan motor relay Model manufacturer ACM33211 M05 MATSUSHITA Fuses Main fuse 20 0 A Headlight fuse 15 0 A Signaling system fuse 7 5 A Ignition fuse 7 5 A Radiator fan fuse 5 0 A Spare fuse 20 0 A Spare fuse 15 0 A Spare fuse 7 5 A Spare fuse 7 5 A YamahaR125 COM ...

Page 38: ...id warpage tight en multi fastener assemblies in a crisscross pat tern and progressive stages until the specified tightening torque is reached Unless otherwise specified tightening torque specifications re quire clean dry threads Components should be at room temperature A Distance between flats B Outside thread diameter A nut B bolt General tightening torques Nm m kg ft lb 10 mm 6 mm 6 0 6 4 3 12 ...

Page 39: ...ond No 1215 Radiator bolt M6 3 10 Nm 1 0 m kg 7 2 ft lb Radiator fan bolt M6 2 8 Nm 0 8 m kg 5 8 ft lb Coolant reservoir bolt M6 2 7 Nm 0 7 m kg 5 1 ft lb Water pump assembly bolt M6 2 10 Nm 1 0 m kg 7 2 ft lb Water pump assembly bolt M6 1 10 Nm 1 0 m kg 7 2 ft lb Water pump housing cover bolt M6 4 10 Nm 1 0 m kg 7 2 ft lb Impeller shaft retainer bolt M6 2 10 Nm 1 0 m kg 7 2 ft lb Thermostat cover...

Page 40: ...ut M12 1 60 Nm 6 0 m kg 43 ft lb Clutch spring bolt M6 4 12 Nm 1 2 m kg 8 7 ft lb Short clutch push rod locknut M6 1 8 Nm 0 8 m kg 5 8 ft lb Clutch boss nut M14 1 70 Nm 7 0 m kg 50 ft lb Drive sprocket retainer bolt M6 2 10 Nm 1 0 m kg 7 2 ft lb Crankcase bearing retainer bolt M6 2 7 Nm 0 7 m kg 5 1 ft lb Shift drum segment screw M6 1 12 Nm 1 2 m kg 8 7 ft lb Stopper lever bolt M6 1 10 Nm 1 0 m kg...

Page 41: ... Generator cover tightening sequence Clutch cover tightening sequence Crankcase tightening sequence 4 2 6 5 3 1 3 11 5 1 6 7 8 4 2 10 9 11 2 12 10 9 9 6 8 1 7 3 13 6 5 4 A 1 6 2 12 5 4 3 13 11 10 9 8 7 14 15 B A Left crankcase B Right crankcase YamahaR125 COM ...

Page 42: ... lb Front fender bolt M6 2 7 Nm 0 7 m kg 5 1 ft lb Side panel upper bolt M6 2 7 Nm 0 7 m kg 5 1 ft lb Damper rod bolt M10 2 28 Nm 2 8 m kg 20 ft lb Front fender stabilizer bolt M6 4 9 Nm 0 9 m kg 6 5 ft lb Grip end M16 2 26 Nm 2 6 m kg 19 ft lb Clutch lever holder bolt M6 1 9 Nm 0 9 m kg 6 5 ft lb Engine mounting nut front side M10 1 46 Nm 4 6 m kg 33 ft lb Engine mounting nut rear upper side M10 ...

Page 43: ... bleed screw M8 1 14 Nm 1 4 m kg 10 ft lb Rear brake pad retaining bolt M10 2 18 Nm 1 8 m kg 13 ft lb Rear brake hose holder M6 1 7 Nm 0 7 m kg 5 1 ft lb Rear brake light switch M10 1 24 Nm 2 4 m kg 17 ft lb Front brake hose holder M6 1 7 Nm 0 7 m kg 5 1 ft lb Speed sensor lead holder M6 1 7 Nm 0 7 m kg 5 1 ft lb Shift arm bolt M6 1 10 Nm 1 0 m kg 7 2 ft lb Main switch bolt M6 2 11 Nm 1 1 m kg 8 0...

Page 44: ...TIGHTENING TORQUES 2 21 Retighten the lower ring nut to 13 Nm 1 3 m kg 9 4 ft lb with a torque wrench YamahaR125 COM ...

Page 45: ... arm inner surface Decompression arm pivoting point Engine oil drain plug O ring Oil pump driven gear shaft Oil filter cover O ring Intake manifold O ring Fuel injector O ring Timing mark accessing screw O ring Crankshaft end accessing screw O ring Engine oil filler cap O ring Starter clutch gear thrust surfaces and washer Starter clutch rollers and starter clutch gear boss Starter motor O ring St...

Page 46: ...ars Shift drum assembly Shift forks and shift fork guide bar Shift shaft Crankshaft position sensor stator assembly lead grommet Yamaha bond No 1215 Three Bond No 1215 Crankcase mating surfaces Yamaha bond No 1215 Three Bond No 1215 Timing chain tensioner bolt threads Yamaha bond No 1215 Three Bond No 1215 Lubrication point Lubricant E E M M E E E YamahaR125 COM ...

Page 47: ...pacer and oil seal lips Rear brake pedal pivoting point and metal to metal moving parts Steering bearings upper and lower Upper bearing cover seal lip and lower bearing dust seal lip Clutch lever pivoting point Clutch cable end Tube guide throttle grip inner surface and throttle cable Sidestand pivoting point and metal to metal moving parts Sidestand spring to hooks mating point Passenger footrest...

Page 48: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 25 EAS20390 LUBRICATION SYSTEM CHART AND DIAGRAMS EAS20400 ENGINE OIL LUBRICATION CHART 1 6 5 2 4 3 YamahaR125 COM ...

Page 49: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 26 1 Oil pump 2 Oil filter element 3 Crankshaft 4 Camshaft 5 Main axle 6 Drive axle YamahaR125 COM ...

Page 50: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 27 EAS20410 LUBRICATION DIAGRAMS A 1 2 3 4 5 6 7 YamahaR125 COM ...

Page 51: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 28 1 Clutch push lever 2 Main axle 3 Drive axle 4 Crankshaft 5 Oil filter 6 Oil pump assembly 7 Oil strainer A To cylinder head YamahaR125 COM ...

Page 52: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 29 1 2 3 4 YamahaR125 COM ...

Page 53: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 30 1 Camshaft 2 Crankshaft 3 Main axle 4 Drive axle YamahaR125 COM ...

Page 54: ...COOLING SYSTEM DIAGRAMS 2 31 EAS20420 COOLING SYSTEM DIAGRAMS 1 2 3 4 5 6 2 4 8 7 2 5 6 9 YamahaR125 COM ...

Page 55: ...IAGRAMS 2 32 1 Radiator inlet hose 2 Coolant reservoir hose 3 Radiator cap 4 Radiator 5 Coolant reservoir breather hose 6 Coolant reservoir 7 Water pump breather hose 8 Water pump 9 Radiator outlet hose YamahaR125 COM ...

Page 56: ...CABLE ROUTING 2 33 EAS20430 CABLE ROUTING E A A C C D D E E F F G G B B F F G A A G E D D C C A B C D E F G H 3 1 2 3 4 5 6 7 8 8 8 9 9 10 10 11 11 12 13 13 8 13 8 8 13 13 13 14 14 YamahaR125 COM ...

Page 57: ...tors to the horn terminals as shown in the illustration E Secure the plastic locking tie by inserting the projection on the tie into the hole in the front brake pipe bracket and then fasten the speed sensor lead with the tie F Pass the front brake light switch lead between the throttle cable and the front brake hose G Fasten the left headlight assembly lead and sub wire harness to the right headli...

Page 58: ...CABLE ROUTING 2 35 A A B B D D C C A B C D 2 1 2 3 4 5 6 6 5 6 7 8 8 8 9 10 11 12 12 12 13 14 15 16 17 18 A A B B C C D D YamahaR125 COM ...

Page 59: ...otor lead 16 Wire harness to coolant temperature sensor 17 Starter motor 18 Front turn signal light lead A Cover the sub wire harness couplers with the coupler cover B Fasten the wire harness and sub wire harness to the guide with a plastic locking tie C After connecting the wire harness to the left and right headlight assembly leads cover the couplers with the coupler cover and then fasten a plas...

Page 60: ...CABLE ROUTING 2 37 A A A B B C C D D E E A C C D E E D B B A 1 1 1 1 1 2 2 2 3 3 3 4 4 4 5 5 YamahaR125 COM ...

Page 61: ...CABLE ROUTING 2 38 1 Battery breather hose 2 Wire harness 3 Starter motor lead 4 Rear brake light switch lead 5 Rear brake hose A Fasten the battery breather hose with the holder YamahaR125 COM ...

Page 62: ...CABLE ROUTING 2 39 D B A F F G G A A B B C C D D E E A B C D E F 1 2 3 3 4 3 4 5 6 6 7 8 8 9 9 10 10 10 11 11 12 13 14 14 15 16 17 18 19 F F G G D B C C A YamahaR125 COM ...

Page 63: ...sure to align the white tape on the leads and cable with the tie B Fasten the sidestand switch lead coolant reservoir hose and fuel tank breather hose with the plastic clamp C Fasten the sidestand switch lead coolant reservoir hose and fuel tank breather hose to the left side cowling bracket with the plastic clamp D Fasten the wire harness to clutch switch and left handlebar switch lead to the lef...

Page 64: ... ROUTING 2 41 L I A A B B C C D D E E F F J J K K G G H H I L D D B B A C A C K K J J E E F F G G H H H H A B C H D E F G 1 2 2 2 2 2 2 2 2 3 4 5 6 6 6 7 8 8 8 9 9 9 10 10 11 12 13 14 15 15 9 YamahaR125 COM ...

Page 65: ...ense plate light lead rear left turn signal light lead and rear right turn signal light lead to the rear fender stay with plastic locking ties making sure to align the white tape on the leads with the ties C Route the fuel tank breather hose and coolant reservoir breather hose so that the end of each hose is positioned further rearward than the sidestand pivoting point as shown in the illustration...

Page 66: ...CABLE ROUTING 2 43 B A A B B C C D D E E A B C D 1 1 2 3 4 4 4 4 5 6 7 7 8 9 10 10 11 11 12 13 14 15 16 17 18 C C E E A A D D B YamahaR125 COM ...

Page 67: ... 12 Clutch cable 13 Throttle cable 14 Wire harness to left handlebar switch 15 Front brake light switch lead 16 Right handlebar switch lead 17 Main switch lead 18 Cylinder head breather hose A Fasten the wire harness with the plastic locking tie B Fasten the fuel injector lead and FID fast idle solenoid lead with a plastic locking tie C Pass the clutch cable through the guide D Secure the plastic ...

Page 68: ...CABLE ROUTING 2 45 A A B C C D D B A A B B C C D D A A B C 1 2 2 3 4 5 5 6 7 8 9 10 11 12 12 13 14 14 15 16 YamahaR125 COM ...

Page 69: ... lead 10 Starting circuit cut off relay 11 Headlight relay 12 ECU engine control unit 13 Wire harness 14 Fuse box 15 Negative battery lead 16 Battery A Fasten the wire harness with a plastic locking tie B Fasten the tail brake light coupler to the frame with a plastic locking tie C Fasten the license plate light lead rear right turn signal light lead rear left turn signal light lead and wire harne...

Page 70: ...CABLE ROUTING 2 47 YamahaR125 COM ...

Page 71: ...E CYLINDER HEAD BREATHER HOSE 3 14 CHECKING THE EXHAUST SYSTEM 3 15 CHECKING THE COOLANT LEVEL 3 15 CHECKING THE COOLING SYSTEM 3 15 CHANGING THE COOLANT 3 15 CHASSIS 3 18 ADJUSTING THE REAR DISC BRAKE 3 18 CHECKING THE BRAKE FLUID LEVEL 3 18 CHECKING THE FRONT BRAKE PADS 3 19 CHECKING THE REAR BRAKE PADS 3 19 CHECKING THE FRONT BRAKE HOSE 3 19 CHECKING THE REAR BRAKE HOSE 3 20 BLEEDING THE HYDRAU...

Page 72: ...ELECTRICAL SYSTEM 3 27 CHECKING AND CHARGING THE BATTERY 3 27 CHECKING THE FUSES 3 27 REPLACING THE HEADLIGHT BULBS 3 27 ADJUSTING THE HEADLIGHT BEAMS 3 28 YamahaR125 COM ...

Page 73: ...YamahaR125 COM ...

Page 74: ...00 km 3500 mi 12000 km 7000 mi 18000 km 10500 mi 24000 km 14000 mi 1 Fuel line Check fuel hoses for cracks or damage 2 Spark plug Check condition Clean and regap Replace 3 Valves Check valve clearance Adjust 4 Air filter element Clean Replace 5 Battery Check electrolyte level and specific gravity Make sure that the breather hose is properly routed 6 Clutch Check operation Adjust 7 Front brake Chec...

Page 75: ... 21 Rear suspension relay arm and connecting arm pivoting points Check operation Lubricate with lithium soap based grease 22 Fuel injection Adjust engine idling speed 23 Engine oil Change 2000 km 1200 mi after the initial 1000 km 600 mi and ev ery 3000 km 1800 mi thereafter Check oil level and vehicle for oil leakage Every 3000 km 1800 mi 24 Engine oil filter el ement Replace 25 Cooling system Che...

Page 76: ...3 Left handlebar switch couplers 4 Cylinder head cover Cylinder head cover gasket Refer to CYLINDER HEAD on page 5 7 NOTE When removing the cylinder head cover lift it out from between the frame tubes 5 Remove Timing mark accessing screw 1 Crankshaft end accessing screw 2 6 Measure Valve clearance Out of specification Adjust a Turn the crankshaft counterclockwise b Align the TDC mark a on the gene...

Page 77: ... with the O ring 9 Install Cylinder head cover gasket Cylinder head cover Spark plug Refer to CYLINDER HEAD on page 5 7 10 Connect Left handlebar switch couplers 1 Main switch coupler 2 11 Install Plastic locking tie 3 NOTE Fasten the wire harness to horn wire harness to left handlebar switch front brake light switch lead right handlebar switch lead and main switch lead to the frame with a plastic...

Page 78: ...nostic mode DIAG 7 After selecting CO press the MODE but ton 8 Check that C1 appears on the LCD of the FI diagnostic tool and then press the MODE button 9 Start the engine CAUTION ECA5D71023 Perform the adjustment after the battery has been sufficiently charged 10 Change the CO adjustment volume by press ing the UP and DOWN buttons NOTE The CO adjustment volume and engine idling speed appears on t...

Page 79: ...b tained 8 Remove Digital tachometer 9 Install Fuel tank Refer to FUEL TANK on page 7 1 Right side panel Rider seat Refer to GENERAL CHASSIS on page 4 1 10 Adjust Throttle cable free play Refer to ADJUSTING THE THROTTLE CA BLE FREE PLAY on page 3 6 EAS20660 ADJUSTING THE THROTTLE CABLE FREE PLAY NOTE Prior to adjusting the throttle cable free play the engine idling speed should be adjusted 1 Check...

Page 80: ... cover Refer to GENERAL CHASSIS on page 4 1 2 Disconnect Spark plug cap 3 Remove Spark plug CAUTION ECA13330 Before removing the spark plug blow away any dirt accumulated in the spark plug well with compressed air to prevent it from falling into the cylinder 4 Check Spark plug type Incorrect Change 5 Check Electrode 1 Damage wear Replace the spark plug Insulator 2 Abnormal color Replace the spark ...

Page 81: ...el tank Do not disconnect the fuel hose fuel drain hose and couplers Refer to FUEL TANK on page 7 1 4 Connect Timing light 1 Digital tachometer 5 Check Ignition timing a Start the engine warm it up for several min utes and then let it run at the specified en gine idling speed b Check that stationary pointer a in the gener ator cover is within the firing range b on the generator rotor Incorrect fir...

Page 82: ...to blow away any dirt accumulat ed in the spark plug well to prevent it from falling into the cylinder 7 Install Extension 1 Compression gauge 2 8 Measure Compression pressure Out of specification Refer to steps c and d a Set the main switch to ON b With the throttle wide open crank the engine until the reading on the compression gauge stabilizes c If the compression pressure is above the maximum ...

Page 83: ...until the oil has settled Do not screw the engine oil filler cap dipstick 1 in when checking the oil level CAUTION ECA5D71027 Engine oil also lubricates the clutch and the wrong oil types or additives could cause clutch slippage Therefore do not add any chemical additives or use engine oils with a grade of CD c or higher and do not use oils labeled ENERGY CONSERVING II d Do not allow foreign mater...

Page 84: ... the own er s tool kit 5 Remove Engine oil filler cap dipstick 1 Engine oil drain plug 2 O ring 3 Spring 4 Engine oil strainer 5 6 Drain Engine oil completely from the crankcase 7 If the oil filter element is also to be replaced perform the following procedure a Remove the oil filter element cover 1 and oil filter element 2 b Install the new O ring 3 c Install the new oil filter element and the oi...

Page 85: ...pecification 16 Install Right lower side cowling Right upper side cowling Right bottom side cowling Refer to GENERAL CHASSIS on page 4 1 EAS20870 ADJUSTING THE CLUTCH CABLE FREE PLAY 1 Check Clutch cable free play a Out of specification Adjust 2 Adjust Clutch cable free play Handlebar end a Pull back the rubber cover 1 b Loosen the locknut 2 c Turn the adjusting bolt 3 in direction a or b until th...

Page 86: ...AIR FILTER ELEMENT NOTE There is a check hose 1 at the bottom of the air filter case If dust and or water collects in this hose clean the air filter element and air filter case 1 Remove Rider seat Refer to GENERAL CHASSIS on page 4 1 2 Remove Fuel tank Refer to FUEL TANK on page 7 1 3 Remove Air filter case cover 1 Air filter element 4 Clean Air filter element 1 Apply compressed air to the outer s...

Page 87: ...hrottle body joint 1 Air filter case joint 2 Cracks damage Replace 3 Install Right lower side cowling Left lower side cowling Refer to GENERAL CHASSIS on page 4 1 EAS21030 CHECKING THE FUEL LINE 1 Remove Left side panel Refer to GENERAL CHASSIS on page 4 1 2 Lift the fuel tank Do not disconnect the fuel hose drain hose and couplers 3 Check Fuel hose 1 Cracks damage Replace Loose connection Connect...

Page 88: ...nt If water is used instead of coolant check and if nec essary correct the antifreeze concentra tion of the coolant Use only distilled water However if dis tilled water is not available soft water may be used 3 Start the engine warm it up for several min utes and then turn it off 4 Check Coolant level NOTE Before checking the coolant level wait a few minutes until it settles EAS21120 CHECKING THE ...

Page 89: ... from the coolant reservoir 8 Connect Coolant reservoir hose 9 Install Coolant drain bolt along with the copper washer 10 Fill Cooling system with the specified amount of the recom mended coolant Handling notes for coolant Coolant is potentially harmful and should be handled with special care WARNING EWA13040 If coolant splashes in your eyes thorough ly wash them with water and consult a doc tor I...

Page 90: ...painted surfaces immediately wash them with wa ter Do not mix different types of antifreeze 11 Install Radiator cap 12 Fill Coolant reservoir with the recommended coolant to the maxi mum level mark a 13 Install Coolant reservoir cap 14 Start the engine warm it up for several min utes and then turn it off 15 Check Coolant level Refer to CHECKING THE COOLANT LEV EL on page 3 15 NOTE Before checking ...

Page 91: ...hicle is operated the air must be removed by bleeding the brake system Air in the brake system will consid erably reduce braking performance CAUTION ECA13510 After adjusting the brake pedal position make sure there is no brake drag e Install the pin washer and cotter pin WARNING EWA5D71019 Always use a new cotter pin EAS21240 CHECKING THE BRAKE FLUID LEVEL 1 Stand the vehicle on a level surface NO...

Page 92: ...y NOTE In order to ensure a correct reading of the brake fluid level make sure the top of the brake fluid reservoir is horizontal EAS21250 CHECKING THE FRONT BRAKE PADS The following procedure applies to all of the brake pads 1 Operate the brake 2 Check Front brake pad Wear indicator grooves a have almost dis appeared Replace the brake pads as a set Refer to FRONT BRAKE on page 4 17 EAS21260 CHECK...

Page 93: ...operation is faulty NOTE Be careful not to spill any brake fluid or allow the brake master cylinder reservoir or brake fluid reservoir to overflow When bleeding the hydraulic brake system make sure there is always enough brake fluid before applying the brake Ignoring this pre caution could allow air to enter the hydraulic brake system considerably lengthening the bleeding procedure If bleeding is ...

Page 94: ...damage the swing arm or cause an accident Therefore keep the drive chain slack within the specified lim its 1 Stand the vehicle on a level surface WARNING EWA13120 Securely support the vehicle so that there is no danger of it falling over NOTE Both wheels should be on the ground without a rider on the vehicle 2 Turn the rear wheel several times and find the tightest position on the drive chain 3 C...

Page 95: ... EWA13120 Securely support the vehicle so that there is no danger of it falling over NOTE Place the vehicle on a suitable stand so that the front wheel is elevated 2 Check Steering head Grasp the bottom of the front fork legs and gently rock the front fork Binding looseness Adjust the steering head 3 Remove Upper bracket Refer to STEERING HEAD on page 4 52 4 Adjust Steering head a Remove the lock ...

Page 96: ...rely support the vehicle so that there is no danger of it falling over 2 Check Inner tube Damage scratches Replace Oil seal Oil leakage Replace 3 Hold the vehicle upright and apply the front brake 4 Check Front fork operation Push down hard on the handlebar several times and check if the front fork rebounds smoothly Rough movement Repair Refer to FRONT FORK on page 4 44 EAS21650 CHECKING THE TIRES...

Page 97: ...ive tests the tires listed below have been approved by MBK Industrie for this model The front and rear tires should al ways be by the same manufacturer and of the same design No guarantee concerning handling characteristics can be given if a tire combination other than one approved by MBK Industrie is used on this vehicle Tire air pressure measured on cold tires Loading condition 0 90 kg 0 198 lb ...

Page 98: ...place damaged outer cable and inner cables as soon as possible 1 Check Outer cable Damage Replace 2 Check Cable operation Rough movement Lubricate NOTE Hold the cable end upright and pour a few drops of lubricant into the cable sheath or use a suit able lubricating device EAS5D71038 LUBRICATING THE CLUTCH LEVER Lubricate the pivoting point and metal to metal moving parts of the lever EAS5D71039 LU...

Page 99: ...CHASSIS 3 26 EAS21740 LUBRICATING THE REAR SUSPENSION Lubricate the pivoting point and metal to metal moving parts of the rear suspension Recommended lubricant Lithium soap based grease YamahaR125 COM ...

Page 100: ...ds away from the bulb until it has cooled down 4 Install Headlight bulb Secure the new headlight bulb with the head light bulb holder CAUTION ECA13690 Avoid touching the glass part of the head light bulb to keep it free from oil otherwise the transparency of the glass the life of the bulb and the luminous flux will be adversely affected If the headlight bulb gets soiled thoroughly clean it with a ...

Page 101: ...he glass the life of the bulb and the luminous flux will be adversely affected If the headlight bulb gets soiled thoroughly clean it with a cloth moistened with alcohol or lacquer thinner 6 Install Headlight bulb holder 7 Connect Headlight coupler 8 Install Headlight bulb cover EAS21810 ADJUSTING THE HEADLIGHT BEAMS The following procedure applies to both of the headlights 1 Adjust Headlight beam ...

Page 102: ...ELECTRICAL SYSTEM 3 29 YamahaR125 COM ...

Page 103: ...E FRONT BRAKE DISC 4 21 REPLACING THE FRONT BRAKE PADS 4 22 REMOVING THE FRONT BRAKE CALIPER 4 23 CHECKING THE FRONT BRAKE CALIPER 4 23 ASSEMBLING THE FRONT BRAKE CALIPER 4 23 INSTALLING THE FRONT BRAKE CALIPER 4 24 REMOVING THE FRONT BRAKE MASTER CYLINDER 4 25 CHECKING THE FRONT BRAKE MASTER CYLINDER 4 25 ASSEMBLING THE FRONT BRAKE MASTER CYLINDER 4 25 INSTALLING THE FRONT BRAKE MASTER CYLINDER 4...

Page 104: ...EERING HEAD 4 54 REAR SHOCK ABSORBER ASSEMBLY 4 56 REMOVING THE REAR SHOCK ABSORBER ASSEMBLY 4 57 CHECKING THE REAR SHOCK ABSORBER ASSEMBLY 4 57 CHECKING THE CONNECTING ARMS AND RELAY ARM 4 57 INSTALLING THE RELAY ARM 4 57 INSTALLING THE REAR SHOCK ABSORBER ASSEMBLY 4 57 SWINGARM 4 59 REMOVING THE SWINGARM 4 61 CHECKING THE SWINGARM 4 61 INSTALLING THE SWINGARM 4 62 CHAIN DRIVE 4 63 REMOVING THE D...

Page 105: ...YamahaR125 COM ...

Page 106: ...arks 1 Rider seat 1 2 Passenger seat 1 3 Negative battery lead 1 Disconnect 4 Positive battery lead 1 Disconnect 5 Battery band 1 6 Battery 1 7 Battery breather hose 1 Disconnect For installation reverse the removal proce dure 3 4 6 7 5 1 2 T R 30 Nm 3 0 m kg 22 ft Ib T R 11 Nm 1 1 m kg 8 0 ft Ib YamahaR125 COM ...

Page 107: ...s to remove Q ty Remarks Rider seat Passenger seat Refer to GENERAL CHASSIS on page 4 1 1 Side panel 2 2 Rear panel 1 3 Rear side cowling 2 For installation reverse the removal proce dure 3 3 1 1 2 T R 7 Nm 0 7 m kg 5 1 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib YamahaR125 COM ...

Page 108: ...ge 4 1 1 Side cover 2 2 Upper side cowling 2 3 Front turn signal light coupler 2 4 Bottom cowling 2 5 Lower side cowling 2 6 Fuel tank cap 1 7 Fuel tank cover 1 8 Front panel 2 9 Sub wire harness coupler 5 10 Front cowling assembly 1 For installation reverse the removal proce dure 3 3 1 1 2 2 8 8 4 5 5 9 10 4 7 6 T R 23 Nm 2 3 m kg 17 ft Ib YamahaR125 COM ...

Page 109: ... 2 Air filter element 1 3 Air filter case seal 2 4 Air filter case joint clamp screw 1 Loosen 5 Air filter case 1 6 Cylinder head breather hose 1 Disconnect 7 Air induction system hose air filter case to reed valve assembly 1 Disconnect 8 Air filter case silencer hose 1 For installation reverse the removal proce dure 1 2 4 6 7 5 3 3 T R 10 Nm 1 0 m kg 7 2 ft Ib T R 2 Nm 0 2 m kg 1 4 ft Ib 8 Yamaha...

Page 110: ...HASSIS 4 5 EAS5D71027 INSTALLING THE AIR FILTER CASE 1 Install Air filter case joint clamp NOTE Align the projection a on the air filter case with the slot b in the air filter case joint clamp a b YamahaR125 COM ...

Page 111: ...ont brake caliper 1 3 Front wheel axle pinch bolt 1 4 Front wheel axle 1 5 Front wheel 1 6 Speed sensor 1 7 Collar 1 8 Front brake disc 1 9 Speed sensor lead holder 1 For installation reverse the removal proce dure LS LT LT 4 9 5 7 8 6 5 LS 1 2 3 T R 7 Nm 0 7 m kg 5 1 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib T R 30 Nm 3 0 m kg 22 ft Ib T R 14 Nm 1 4 m kg 10 ft Ib T R 18 Nm 1 8 m kg 13 ft Ib T R 59 Nm 5 9...

Page 112: ...T WHEEL 4 7 Disassembling the front wheel Order Job Parts to remove Q ty Remarks 1 Oil seal 1 2 Bearing 1 3 Spacer 1 4 Bearing 1 For assembly reverse the disassembly pro cedure New 1 2 3 4 LS YamahaR125 COM ...

Page 113: ...l hub b Remove the oil seal 1 with a flat head screwdriver NOTE To prevent damaging the wheel place a rag 2 between the screwdriver and the wheel surface c Remove the wheel bearings 3 with a gener al bearing puller EAS21920 CHECKING THE FRONT WHEEL 1 Check Front wheel axle Roll the wheel axle on a flat surface Bends Replace WARNING EWA13460 Do not attempt to straighten a bent wheel ax le 2 Check T...

Page 114: ...ter of the wheel bearing outer race and oil seal EAS21970 ADJUSTING THE FRONT WHEEL STATIC BALANCE NOTE After replacing the tire wheel or both the front wheel static balance should be adjusted Adjust the front wheel static balance with the brake discs installed 1 Remove Balancing weight s 2 Find Front wheel s heavy spot NOTE Place the front wheel on a suitable balancing stand a Spin the front whee...

Page 115: ...si tion install a heavier weight d Repeat steps b and c until the front wheel is balanced 4 Check Front wheel static balance a Turn the front wheel and make sure it stays at each position shown b If the front wheel does not remain stationary at all of the positions rebalance it EAS21990 INSTALLING THE FRONT WHEEL DISC 1 Install Front brake disc NOTE Be sure to install the front brake disc with the...

Page 116: ...el axle from the right side and tighten it from the left side to 59 Nm 5 9 m kg 43 ft lb without performing temporary tightening b Tighten the front wheel axle pinch bolt to 14 Nm 1 4 m kg 10 ft lb without performing temporary tightening c Check that the right end of the front wheel axle is flush with the front fork If necessary manually push the front wheel axle or lightly tap it with a soft hamm...

Page 117: ...d 1 Drive chain guard 1 2 Drive chain adjusting locknut 2 Loosen 3 Drive chain adjusting bolt 2 Loosen 4 Rear wheel axle nut 1 5 Rear wheel axle 1 6 Drive chain puller 2 7 Rear wheel 1 8 Collar 1 9 Collar 1 For installation reverse the removal proce dure 4 6 LT 2 3 8 6 9 1 5 7 T R 85 Nm 8 5 m kg 61 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib YamahaR125 COM ...

Page 118: ... Remarks 1 Rear brake disc 1 2 Rear wheel sprocket 1 3 Oil seal 1 4 Bearing 1 5 Rear wheel drive hub 1 6 Collar 1 7 Rear wheel drive hub damper 4 For installation reverse the removal proce dure 4 6 7 6 5 1 5 3 New LS LS 2 LT T R 18 Nm 1 8 m kg 13 ft Ib T R 43 Nm 4 3 m kg 31 ft Ib YamahaR125 COM ...

Page 119: ... WHEEL 4 14 Disassembling the rear wheel Order Job Parts to remove Q ty Remarks 1 Bearing 1 2 Spacer 1 3 Oil seal 1 4 Bearing 1 For assembly reverse the disassembly pro cedure LS 1 3 2 New 4 YamahaR125 COM ...

Page 120: ...THE REAR WHEEL 1 Check Rear wheel axle Rear wheel Wheel bearings Oil seals Refer to CHECKING THE FRONT WHEEL on page 4 8 2 Check Tire Rear wheel Damage wear Replace Refer to CHECKING THE TIRES on page 3 23 and CHECKING THE WHEELS on page 3 25 3 Measure Radial wheel runout Lateral wheel runout Refer to CHECKING THE FRONT WHEEL on page 4 8 EAS5D71042 CHECKING THE REAR BRAKE CALIPER BRACKET 1 Check R...

Page 121: ...ith the brake disc and rear wheel drive hub installed 1 Adjust Rear wheel static balance Refer to ADJUSTING THE FRONT WHEEL STATIC BALANCE on page 4 9 EAS22160 INSTALLING THE REAR WHEEL DISC 1 Install Rear brake disc NOTE Tighten the brake disc bolts in stages and in a crisscross pattern 2 Check Rear brake disc Refer to CHECKING THE REAR BRAKE DISC on page 4 33 3 Lubricate Rear wheel axle Contact ...

Page 122: ...der 1 2 Front brake caliper bolt 2 3 Front brake caliper 1 4 Brake pad clip 2 5 Brake pad pin 1 6 Front brake pad 2 7 Brake pad spring 1 8 Brake pad support 1 For installation reverse the removal proce dure T R 7 Nm 0 7 m kg 5 1 ft Ib T R 30 Nm 3 0 m kg 22 ft Ib 2 6 4 5 3 1 LT 7 8 T R 14 Nm 1 4 m kg 10 ft Ib YamahaR125 COM ...

Page 123: ...linder reservoir cap 1 2 Brake master cylinder reservoir diaphragm 1 3 Front brake light switch 1 4 Brake hose union bolt 1 5 Copper washer 2 6 Front brake hose 1 7 Brake lever 1 8 Front brake master cylinder holder 1 9 Front brake master cylinder 1 For installation reverse the removal proce dure S T R 30 Nm 3 0 m kg 22 ft Ib T R 9 Nm 0 9 m kg 6 5 ft Ib New 4 3 6 5 8 9 7 1 2 YamahaR125 COM ...

Page 124: ...ULIC BRAKE SYSTEM on page 3 20 1 Brake hose holder 1 2 Brake hose union bolt 1 3 Copper washer 2 4 Front brake hose 1 5 Front brake caliper bolt 2 6 Front brake caliper 1 For installation reverse the removal proce dure 6 3 2 4 5 1 New T R 7 Nm 0 7 m kg 5 1 ft Ib T R 30 Nm 3 0 m kg 22 ft Ib T R 30 Nm 3 0 m kg 22 ft Ib LT YamahaR125 COM ...

Page 125: ...r Job Parts to remove Q ty Remarks 1 Brake pad clip 2 2 Brake pad pin 1 3 Brake pad 2 4 Brake pad spring 1 5 Brake caliper bracket 1 6 Brake pad support 1 7 Brake caliper body 1 For assembly reverse the disassembly pro cedure 5 1 4 7 2 1 3 6 S S YamahaR125 COM ...

Page 126: ...ve Front wheel Refer to FRONT WHEEL on page 4 6 2 Check Brake disc Damage galling Replace 3 Measure Brake disc deflection Out of specification Correct the brake disc deflection or replace the brake disc a Place the vehicle on a suitable stand so that the front wheel is elevated b Before measuring the front brake disc deflec tion turn the handlebar to the left or right to ensure that the front whee...

Page 127: ...Brake pads NOTE Always install new brake pads a new brake pad spring and a new brake pad support as a set a Connect a clear plastic hose 1 tightly to the bleed screw 2 Put the other end of the hose into an open container b Loosen the bleed screw and push the brake caliper pistons into the brake caliper with your fingers c Tighten the bleed screw d Install new brake pad support a new brake pad spri...

Page 128: ...body 2 Cracks damage Replace the brake caliper assembly Brake fluid delivery passages brake caliper body Obstruction Blow out with compressed air WARNING EWA5D71012 Whenever a brake caliper is disassembled replace the brake caliper piston dust seals and piston seals 2 Check Brake caliper bracket Cracks damage Replace EAS22400 ASSEMBLING THE FRONT BRAKE CALIPER WARNING EWA5D71013 Before installatio...

Page 129: ...s may cause the rubber seals to deteriorate causing leakage and poor brake performance Refill with the same type of brake fluid that is already in the system Mixing brake fluids may result in a harmful chemical reaction leading to poor brake performance When refilling be careful that water does not enter the brake master cylinder reser voir Water will significantly lower the boil ing point of the ...

Page 130: ... with compressed air 2 Check Brake master cylinder reservoir Cracks damage Replace the brake master cylinder Brake master cylinder reservoir diaphragm Damage wear Replace 3 Check Brake hose Cracks damage wear Replace EAS22520 ASSEMBLING THE FRONT BRAKE MASTER CYLINDER WARNING EWA13520 Before installation all internal brake com ponents should be cleaned and lubricated with clean or new brake fluid ...

Page 131: ... the specified amount of the recom mended brake fluid WARNING EWA13540 Use only the designated brake fluid Other brake fluids may cause the rubber seals to deteriorate causing leakage and poor brake performance Refill with the same type of brake fluid that is already in the system Mixing brake fluids may result in a harmful chemical reaction leading to poor brake performance When refilling be care...

Page 132: ...FRONT BRAKE 4 27 7 Check Brake lever operation Soft or spongy feeling Bleed the brake sys tem Refer to BLEEDING THE HYDRAULIC BRAKE SYSTEM on page 3 20 a YamahaR125 COM ...

Page 133: ...move Q ty Remarks Rear wheel Refer to REAR WHEEL on page 4 12 1 Rear brake caliper 1 2 Brake pad retaining bolt 2 3 Rear brake pad 2 4 Brake pad spring 1 For installation reverse the removal proce dure LT 2 1 2 4 3 T R 18 Nm 1 8 m kg 13 ft Ib T R 14 Nm 1 4 m kg 10 ft Ib LT YamahaR125 COM ...

Page 134: ...cap 1 3 Brake fluid reservoir diaphragm holder 1 4 Brake fluid reservoir diaphragm 1 5 Brake fluid reservoir 1 6 Brake fluid reservoir hose 1 7 Rear brake light switch coupler 1 Disconnect 8 Rear brake master cylinder bolt 2 9 Rear brake master cylinder 1 10 Rear brake light switch 1 11 Copper washer 2 12 Rear brake hose 1 For installation reverse the removal proce dure 8 9 8 11 12 T R 24 Nm 2 4 m...

Page 135: ...master cylinder Order Job Parts to remove Q ty Remarks 1 Brake hose joint 1 2 Brake master cylinder kit 1 3 Brake master cylinder body 1 For assembly reverse the disassembly pro cedure New New New 1 2 3 S T R 17 Nm 1 7 m kg 12 ft Ib YamahaR125 COM ...

Page 136: ...BLEEDING THE HYDRAULIC BRAKE SYSTEM on page 3 20 Rear wheel Refer to REAR WHEEL on page 4 12 1 Rear brake hose union bolt 1 2 Copper washer 2 3 Rear brake hose 1 4 Rear brake caliper 1 For installation reverse the removal proce dure 4 2 1 3 T R 7 Nm 0 7 m kg 5 1 ft Ib T R 30 Nm 3 0 m kg 22 ft Ib New YamahaR125 COM ...

Page 137: ... Rear brake pad 2 3 Brake pad spring 1 4 Brake caliper bracket 1 5 Brake caliper piston 1 6 Brake caliper piston dust seal 1 7 Brake caliper piston seal 1 8 Bleed screw 1 For assembly reverse the disassembly pro cedure 1 1 3 2 5 7 6 4 8 T R 18 Nm 1 8 m kg 13 ft Ib T R 14 Nm 1 4 m kg 10 ft Ib New New BF S S S YamahaR125 COM ...

Page 138: ...n page 4 12 2 Check Brake disc Damage galling Replace 3 Measure Brake disc deflection Out of specification Correct the brake disc deflection or replace the brake disc Refer to CHECKING THE FRONT BRAKE DISC on page 4 21 4 Measure Brake disc thickness Measure the brake disc thickness at a few dif ferent locations Out of specification Replace Refer to CHECKING THE FRONT BRAKE DISC on page 4 21 5 Adju...

Page 139: ... WHEEL on page 4 12 6 Check Brake fluid level Below the minimum level mark a Add the recommended brake fluid to the proper level Refer to CHECKING THE BRAKE FLUID LEVEL on page 3 18 7 Check Brake pedal operation Soft or spongy feeling Bleed the brake sys tem Refer to BLEEDING THE HYDRAULIC BRAKE SYSTEM on page 3 20 EAS22590 REMOVING THE REAR BRAKE CALIPER NOTE Before disassembling the brake calipe...

Page 140: ...ke caliper Never try to pry out the brake caliper pis ton b Remove the brake caliper piston seal and dust seal EAS22640 CHECKING THE REAR BRAKE CALIPER 1 Check Brake caliper piston 1 Rust scratches wear Replace the brake caliper piston Brake caliper cylinder 2 Scratches wear Replace the brake caliper assembly Brake caliper body 3 Cracks damage Replace the brake caliper assembly Brake fluid deliver...

Page 141: ... pipe a into the slot b in the brake caliper 2 Install Brake pad spring Brake pads Brake pad retaining bolts Rear brake caliper Refer to REPLACING THE REAR BRAKE PADS on page 4 33 3 Install Rear wheel Refer to REAR WHEEL on page 4 12 4 Fill Brake fluid reservoir with the specified amount of the recom mended brake fluid WARNING EWA13090 Use only the designated brake fluid Other brake fluids may cau...

Page 142: ...linder 4 Remove Rear brake light switch 1 Copper washers 2 Brake hose 3 NOTE To collect any remaining brake fluid place a container under the master cylinder and the end of the brake hose EAS22720 CHECKING THE REAR BRAKE MASTER CYLINDER 1 Check Brake master cylinder Damage scratches wear Replace Brake fluid delivery passages brake master cylinder body Obstruction Blow out with compressed air 2 Che...

Page 143: ...mical reaction leading to poor brake performance When refilling be careful that water does not enter the brake fluid reservoir Water will significantly lower the boiling point of the brake fluid and could cause vapor lock CAUTION ECA13540 Brake fluid may damage painted surfaces and plastic parts Therefore always clean up any spilt brake fluid immediately 3 Bleed Brake system Refer to BLEEDING THE ...

Page 144: ...older 1 9 Right grip end 1 10 Right handlebar switch 1 11 Throttle cable 1 Disconnect 12 Throttle grip 1 13 Front brake light switch 1 14 Front brake master cylinder holder 1 15 Front brake master cylinder 1 16 Plug 2 2 1 3 4 5 6 7 8 9 11 12 13 14 4 20 19 16 17 18 17 16 18 10 10 15 T R 9 Nm 0 9 m kg 6 5 ft Ib T R 9 Nm 0 9 m kg 6 5 ft Ib T R 9 Nm 0 9 m kg 6 5 ft Ib LS LS LS LS LS T R 26 Nm 2 6 m kg...

Page 145: ...al proce dure Removing the handlebars Order Job Parts to remove Q ty Remarks 2 1 3 4 5 6 7 8 9 11 12 13 14 4 20 19 16 17 18 17 16 18 10 10 15 T R 9 Nm 0 9 m kg 6 5 ft Ib T R 9 Nm 0 9 m kg 6 5 ft Ib T R 9 Nm 0 9 m kg 6 5 ft Ib LS LS LS LS LS T R 26 Nm 2 6 m kg 19 ft Ib T R 26 Nm 2 6 m kg 19 ft Ib T R 23 Nm 2 3 m kg 17 ft Ib YamahaR125 COM ...

Page 146: ...arrow mark a pointing forward Align the mating surfaces of the brake master cylinder holder with the punch mark b on the handlebar First tighten the front bolt then the rear bolt 3 Install Front brake light switch NOTE Before fully installing the front brake light switch be sure to completely install the rubber cover over the switch Also be sure not to twist the front brake light switch lead when ...

Page 147: ...e end of the clutch cable with a thin coat of lithium soap based grease 9 Install Left handlebar switch 1 NOTE Align the projection a on the left handlebar switch with the hole b in the left handlebar 10 Connect Clutch switch coupler 11 Install Handlebar grip 1 Left grip end 2 a Apply a thin coat of rubber adhesive onto the end of the left handlebar b Slide the handlebar grip over the end of the l...

Page 148: ...lutch cable and handlebar switch leads are routed properly Refer to CA BLE ROUTING on page 2 33 13 Adjust Clutch lever free play Refer to ADJUSTING THE CLUTCH CABLE FREE PLAY on page 3 12 14 Adjust Throttle cable free play Refer to ADJUSTING THE THROTTLE CA BLE FREE PLAY on page 3 6 Clutch lever free play 10 0 15 0 mm 0 39 0 59 in Throttle cable free play 3 0 5 0 mm 0 12 0 20 in YamahaR125 COM ...

Page 149: ...RONT WHEEL on page 4 6 1 Front fender 1 2 Plug 1 3 Handlebar bolt 1 Loosen 4 Handlebar pinch bolt 1 Loosen 5 Upper bracket pinch bolt 1 Loosen 6 Lower bracket pinch bolt 1 Loosen 7 Front fork leg 1 For installation reverse the removal proce dure 1 6 7 2 3 5 4 4 T R 9 Nm 0 9 m kg 6 5 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib T R 23 Nm 2 3 m kg 17 ft Ib LT T R 28 Nm 2 8 m kg 20 ft Ib YamahaR125 COM ...

Page 150: ...ubber cap 1 2 Clip 1 3 Front fork cap 1 4 O ring 1 5 Spacer 1 6 Washer 1 7 Fork spring 1 8 Dust seal 1 9 Oil seal clip 1 10 Damper rod bolt 1 11 Copper washer 1 12 Damper rod 1 13 Inner tube 1 14 Oil flow stopper 1 15 Oil seal 1 16 Washer 1 8 9 11 10 18 15 16 17 13 14 1 2 3 4 5 6 7 12 New New New New New New New T R 28 Nm 2 8 m kg 20 ft Ib YamahaR125 COM ...

Page 151: ...ter tube 1 For assembly reverse the disassembly pro cedure Disassembling the front fork legs Order Job Parts to remove Q ty Remarks 8 9 11 10 18 15 16 17 13 14 1 2 3 4 5 6 7 12 New New New New New New New T R 28 Nm 2 8 m kg 20 ft Ib YamahaR125 COM ...

Page 152: ...t pinch bolts support the front fork leg 3 Remove Front fork leg EAS22980 DISASSEMBLING THE FRONT FORK LEGS The following procedure applies to both of the front fork legs 1 Remove Rubber cap Clip 1 Front fork cap 2 with O ring Fork spring NOTE Push the front fork cap in the direction of the ar row shown in the illustration to remove the clip 2 Drain Fork oil NOTE Stroke the inner tube several time...

Page 153: ...e front fork EAS23030 ASSEMBLING THE FRONT FORK LEGS The following procedure applies to both of the front fork legs WARNING EWA13660 Make sure the oil levels in both front fork legs are equal Uneven oil levels can result in poor han dling and a loss of stability NOTE When assembling the front fork leg be sure to replace the following parts Outer tube bushing Oil seal Dust seal Clip Before assembli...

Page 154: ...ase Lubricate the outer surface of the inner tube with fork oil Before installing the oil seal cover the top of the front fork leg with a plastic bag to protect the oil seal during installation Recommended oil Fork oil 10W or equivalent T R Damper rod bolt 28 Nm 2 8 m kg 20 ft lb Damper rod holder 90890 01294 Damping rod holder set YM 01300 T handle 90890 01326 T handle 3 8 drive 60 cm long YM 013...

Page 155: ...k leg slowly stroke the inner tube 1 up and down at least ten times to distribute the fork oil NOTE Be sure to stroke the inner tube slowly because the fork oil may spurt out 10 Before measuring the fork oil level wait ten minutes until the oil has settled and the air bubbles have dispersed NOTE Be sure to bleed the front fork leg of any residual air 11 Measure Front fork leg oil level a from the ...

Page 156: ... to both of the front fork legs 1 Install Front fork leg Temporarily tighten the upper and lower bracket pinch bolts NOTE Make sure the inner tube end position a is 24 5 mm 0 96 in from the top of the upper bracket 2 Tighten Lower bracket pinch bolt 1 Upper bracket pinch bolt 2 Handlebar bolt 3 Handlebar pinch bolt 4 WARNING EWA5D71018 Make sure the brake hose clutch cable and leads are routed pro...

Page 157: ...1 1 Front brake pipe bracket 1 2 Steering stem nut 1 3 Upper bracket 1 4 Lock washer 1 5 Upper ring nut 1 6 Rubber washer 1 7 Lower ring nut 1 8 Lower bracket 1 9 Bearing cover 1 10 Upper bearing inner race 1 11 Upper bearing 1 12 Lower bearing 1 2 3 4 5 6 7 9 10 11 13 14 15 8 16 12 1 New T R 7 Nm 0 7 m kg 5 1 ft Ib T R 1st 48 Nm 4 8 m kg 35 ft lb 2nd 13 Nm 1 3 m kg 9 4 ft lb LS LS T R 11 Nm 1 1 m...

Page 158: ...For installation reverse the removal proce dure Removing the lower bracket Order Job Parts to remove Q ty Remarks 2 3 4 5 6 7 9 10 11 13 14 15 8 16 12 1 New T R 7 Nm 0 7 m kg 5 1 ft Ib T R 1st 48 Nm 4 8 m kg 35 ft lb 2nd 13 Nm 1 3 m kg 9 4 ft lb LS LS T R 11 Nm 1 1 m kg 8 0 ft Ib T R 110 Nm 11 0 m kg 80 ft lb YamahaR125 COM ...

Page 159: ...the steering head pipe with a long rod 1 and hammer b Remove the bearing race from the lower bracket with a floor chisel 2 and hammer c Install a new dust seal and new bearing rac es CAUTION ECA5D71039 If the bearing races are not installed proper ly the steering head pipe could be damaged NOTE Always replace the bearings and bearing races as a set Whenever the steering head is disassembled replac...

Page 160: ... 22 3 Install Upper bracket Steering stem nut NOTE Temporarily tighten the steering stem nut 4 Install Front fork legs Refer to FRONT FORK on page 4 44 NOTE Temporarily tighten the upper and lower bracket pinch bolts 5 Tighten Steering stem nut T R Steering stem nut 110 Nm 11 0 m kg 80 ft lb YamahaR125 COM ...

Page 161: ...55 mm 2 Connecting arm nut front bolt 1 1 M10 58 mm 3 Connecting arm 2 4 Rear shock absorber assembly lower nut bolt 1 1 5 Rear shock absorber assembly upper nut bolt 1 1 6 Rear shock absorber assembly 1 7 Relay arm nut bolt 1 1 8 Relay arm 1 9 Spacer 3 10 Oil seal 6 11 Bearing 3 For installation reverse the removal proce dure 5 5 7 7 6 4 4 2 1 3 10 11 New New LS LS 10 9 New 11 10 New 11 8 10 New ...

Page 162: ...sorber assembly Bolts Bends damage wear Replace EAS23260 CHECKING THE CONNECTING ARMS AND RELAY ARM 1 Check Connecting arms Relay arm Damage wear Replace 2 Check Bearings Oil seals Damage pitting Replace 3 Check Spacers Damage scratches Replace EAS23270 INSTALLING THE RELAY ARM 1 Lubricate Spacers Bearings Oil seals Bolts unthreaded shaft portion only 2 Install Bearing 1 to the relay arm Oil seal ...

Page 163: ...nnecting arms NOTE When installing the connecting arms lift up the swingarm 4 Tighten Connecting arm nuts T R Rear shock absorber assembly upper nut 44 Nm 4 4 m kg 32 ft lb T R Relay arm nut 44 Nm 4 4 m kg 32 ft lb T R Rear shock absorber assembly lower nut 44 Nm 4 4 m kg 32 ft lb T R Connecting arm nut 44 Nm 4 4 m kg 32 ft lb FWD 1 YamahaR125 COM ...

Page 164: ...chain Refer to CHAIN DRIVE on page 4 63 1 Drive chain adjusting bolt locknut 2 2 2 Rear fender 1 3 Rear brake hose holder 1 4 Pivot shaft nut 1 5 Pivot shaft 1 6 Swingarm 1 7 Swingarm adjusting collar 1 8 Drive chain guide 1 9 Spacer 1 10 Oil seal 2 11 Bearing 1 T R 7 Nm 0 7 m kg 5 1 ft Ib T R 81Nm 8 1 m kg 59 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib T R 7 Nm 0 7 m kg 5 1 ft I...

Page 165: ...l proce dure Removing the swingarm Order Job Parts to remove Q ty Remarks T R 7 Nm 0 7 m kg 5 1 ft Ib T R 81Nm 8 1 m kg 59 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib LS LS LS 5 4 1 1 6 8 13 12 13 7 3 2 11 14 14 9 10 12 10 New New YamahaR125 COM ...

Page 166: ... nut Pivot shaft Swingarm 1 Swingarm adjusting collar 2 a Loosen the pivot shaft nut b Fully turn in the swingarm adjusting collar so that it contacts the frame 3 c Remove the pivot shaft nut washer pivot shaft and swingarm EAS23360 CHECKING THE SWINGARM 1 Check Swingarm Bends cracks damage Replace 2 Check Pivot shaft Roll the pivot shaft on a flat surface Bends Replace WARNING EWA13770 Do not att...

Page 167: ...sting collar out to tighten it and so that it contacts the dust cover on the swingarm d Tighten the pivot shaft nut e Check the swingarm side play Refer to REMOVING THE SWINGARM on page 4 61 4 Install Rear shock absorber assembly Relay arm Rear wheel Refer to REAR SHOCK ABSORBER AS SEMBLY on page 4 56 and REAR WHEEL on page 4 12 5 Adjust Drive chain slack Refer to ADJUSTING THE DRIVE CHAIN SLACK o...

Page 168: ...1 Rear wheel Refer to REAR WHEEL on page 4 12 1 Drive sprocket cover 1 2 Master link clip 1 3 Master link plate 1 4 O ring 4 5 Master link 1 6 Drive chain 1 7 Drive sprocket retainer 1 8 Drive sprocket 1 For installation reverse the removal proce dure New New New 2 8 7 6 1 T R 10 Nm 1 0 m kg 7 2 ft Ib T R 10 Nm 1 0 m kg 7 2 ft Ib 5 4 3 4 YamahaR125 COM ...

Page 169: ...OTE When measuring a 15 link section of the drive chain make sure that the drive chain is taut Perform this procedure 2 3 times at a different location each time 2 Clean Drive chain a Wipe the drive chain with a clean cloth b Put the drive chain in kerosene and remove any remaining dirt c Remove the drive chain from the kerosene and completely dry it CAUTION ECA14290 This motorcycle has a drive ch...

Page 170: ...VE HUB Refer to CHECKING THE REAR WHEEL DRIVE HUB on page 4 15 EAS23490 INSTALLING THE DRIVE CHAIN 1 Lubricate Drive chain Master link 2 Install Drive sprocket Drive sprocket retainer bolts 3 Install Master link O rings Master link plate Master link clip 1 CAUTION ECA14310 The closed end of the master link clip must face in the direction of drive chain rotation Never install a new drive chain onto...

Page 171: ... Rear wheel Refer to REAR WHEEL on page 4 12 6 Adjust Drive chain slack Refer to ADJUSTING THE DRIVE CHAIN SLACK on page 3 21 CAUTION ECA13550 A drive chain that is too tight will overload the engine and other vital parts and one that is too loose can skip and damage the swing arm or cause an accident Therefore keep the drive chain slack within the specified lim its Drive chain slack 30 0 40 0 mm ...

Page 172: ...CHAIN DRIVE 4 67 YamahaR125 COM ...

Page 173: ...AND ROCKER ARMS 5 16 VALVES AND VALVE SPRINGS 5 17 REMOVING THE VALVES 5 18 CHECKING THE VALVES AND VALVE GUIDES 5 18 CHECKING THE VALVE SEATS 5 20 CHECKING THE VALVE SPRINGS 5 21 INSTALLING THE VALVES 5 22 CYLINDER AND PISTON 5 24 REMOVING THE PISTON 5 25 CHECKING THE CYLINDER AND PISTON 5 25 CHECKING THE PISTON RINGS 5 26 CHECKING THE PISTON PIN 5 27 INSTALLING THE PISTON AND CYLINDER 5 27 GENER...

Page 174: ... 5 50 SHIFT SHAFT 5 51 CHECKING THE SHIFT SHAFT 5 52 CHECKING THE STOPPER LEVER 5 52 INSTALLING THE SHIFT SHAFT 5 52 BALANCER GEAR 5 53 REMOVING THE PRIMARY DRIVE GEAR AND BALANCER GEARS 5 54 CHECKING THE BALANCER GEARS AND PRIMARY DRIVE GEAR 5 54 INSTALLING THE PRIMARY DRIVE GEAR AND BALANCER GEARS 5 54 CRANKCASE 5 56 SEPARATING THE CRANKCASE 5 59 CHECKING THE CRANKCASE 5 59 CHECKING THE TIMING C...

Page 175: ...IFT FORKS 5 67 CHECKING THE SHIFT DRUM ASSEMBLY 5 67 CHECKING THE TRANSMISSION 5 67 CHECKING THE CLUTCH PUSH RODS 5 68 ASSEMBLING THE MAIN AXLE AND DRIVE AXLE 5 68 INSTALLING THE SHIFT FORKS AND SHIFT DRUM ASSEMBLY 5 68 YamahaR125 COM ...

Page 176: ...n page 4 1 1 Air induction system hose reed valve assembly to exhaust pipe 1 Disconnect 2 Exhaust pipe nut 2 3 Exhaust assembly bolt 1 M8 20 mm 4 Exhaust assembly bolt 1 M8 35 mm 5 Exhaust assembly 1 6 Exhaust pipe gasket 1 For installation reverse the removal proce dure 6 2 2 4 5 1 3 New T R 20 Nm 2 0 m kg 14 ft Ib T R 20 Nm 2 0 m kg 14 ft Ib YamahaR125 COM ...

Page 177: ...ne oil Drain Refer to CHANGING THE ENGINE OIL on page 3 11 Coolant Drain Refer to CHANGING THE COOLANT on page 3 15 Fuel tank Refer to FUEL TANK on page 7 1 Throttle body Intake manifold Refer to THROTTLE BODY on page 7 4 Coolant reservoir Water pump breather hose Radiator outlet hose Radiator Refer to RADIATOR on page 6 1 Coolant temperature sensor Thermostat Radia tor inlet hose Refer to THERMOS...

Page 178: ...cking tie 2 4 Stator coil coupler Crankshaft position sensor coupler 1 1 Disconnect 5 Neutral switch connector 1 Disconnect 6 Starter motor lead 1 Disconnect 7 Clutch cable 1 Disconnect 8 Negative battery lead 1 Disconnect 9 Shift arm 1 For installation reverse the removal proce dure Disconnecting the leads and couplers Order Job Parts to remove Q ty Remarks 1 2 3 4 6 7 8 9 5 4 T R 10 Nm 1 0 m kg ...

Page 179: ...stand under the engine 1 Engine mounting bolt nut front side 1 1 2 Engine mounting bolt nut rear lower side 1 1 3 Engine mounting bolt nut rear upper side 1 1 4 Engine 1 For installation reverse the removal proce dure 1 1 2 2 3 3 4 T R 46 Nm 4 6 m kg 33 ft Ib T R 46 Nm 4 6 m kg 33 ft Ib YamahaR125 COM ...

Page 180: ...t rider footrest 2 and the center of the shift pedal 3 is within specification EAS5D71045 INSTALLING THE EXHAUST ASSEMBLY 1 Install Exhaust assembly 1 Exhaust pipe nuts 2 Exhaust assembly bolts 3 4 NOTE Do not fully tighten the nuts and bolts 2 Tighten Exhaust pipe nuts 2 Exhaust assembly bolt 4 Exhaust assembly bolt 3 T R Engine mounting nut rear upper side 46 Nm 4 6 m kg 33 ft lb T R Engine moun...

Page 181: ...ENGINE REMOVAL 5 6 2 2 4 1 3 YamahaR125 COM ...

Page 182: ...iator Coolant reservoir hose Refer to RADIATOR on page 6 1 Thermostat Coolant temperature sensor Refer to THERMOSTAT on page 6 4 Water pump Refer to WATER PUMP on page 6 6 1 Spark plug cap 1 Disconnect 2 Spark plug 1 3 Crankshaft end accessing screw 1 4 Timing mark accessing screw 1 New New New New New New E E E 4 12 11 14 15 16 15 13 6 7 1 2 4 4 10 9 8 5 4 3 5 T R 10 Nm 1 0 m kg 7 2 ft Ib T R 10 ...

Page 183: ... 1 15 Dowel pin 2 16 Timing chain guide exhaust side 1 For installation reverse the removal proce dure Removing the cylinder head Order Job Parts to remove Q ty Remarks New New New New New New E E E 4 12 11 14 15 16 15 13 6 7 1 2 4 4 10 9 8 5 4 3 5 T R 10 Nm 1 0 m kg 7 2 ft Ib T R 10 Nm 1 0 m kg 7 2 ft Ib T R 10 Nm 1 0 m kg 7 2 ft Ib T R 10 Nm 1 0 m kg 7 2 ft Ib T R 13 Nm 1 3 m kg 9 4 ft Ib T R 22...

Page 184: ...cket bolt 3 Remove Camshaft sprocket NOTE To prevent the timing chain from falling into the crankcase fasten it with a wire 1 4 Remove Cylinder head NOTE Loosen the bolts in the proper sequence as shown Loosen each bolt 1 2 of a turn at a time After all of the bolts are fully loosened remove bolts 1 2 4 and 6 and then remove the cylinder head with bolts 3 and 5 installed in the bolt holes EAS24160...

Page 185: ... times EAS5D71031 CHECKING THE CAMSHAFT SPROCKET AND TIMING CHAIN GUIDE 1 Check Camshaft sprocket More than 1 4 tooth wear a Replace the camshaft sprocket timing chain and crank shaft as a set 2 Check Timing chain guide exhaust side Damage wear Replace EAS24200 CHECKING THE TIMING CHAIN TENSIONER 1 Check Timing chain tensioner Cracks damage rough movement Re place a Lightly press the timing chain ...

Page 186: ...ts from the camshaft exhaust cam as shown in the illustration A d Move the decompression lever 1 in the di rection of the arrow shown and check that the decompression cam does not project from the camshaft exhaust cam as shown in the illustration B EAS24230 INSTALLING THE CYLINDER HEAD 1 Install Cylinder head NOTE Pass the timing chain through the timing chain cavity 2 Tighten Cylinder head bolts ...

Page 187: ...mporarily tight en the camshaft sprocket bolt f Remove the wire from the timing chain 4 Install Timing chain tensioner gasket Timing chain tensioner a Apply sealant to the timing chain tensioner bolt threads b While lightly pressing the timing chain ten sioner rod by hand turn the tensioner rod ful ly clockwise with a thin screwdriver 1 c With the timing chain tensioner rod turned all the way into...

Page 188: ...on the cylinder head Out of alignment Correct Refer to the installation steps above 7 Tighten Camshaft sprocket bolt CAUTION ECA5D71013 Be sure to tighten the camshaft sprocket bolt to the specified torque to avoid the possibil ity of the bolt coming loose and damaging the engine 8 Measure Valve clearance Out of specification Adjust Refer to ADJUSTING THE VALVE CLEAR ANCE on page 3 3 T R Camshaft ...

Page 189: ...EAD on page 5 7 1 Locknut 4 2 Adjusting screw 4 3 Camshaft retainer 1 4 Rocker arm shaft 2 5 Intake rocker arm 1 6 Exhaust rocker arm 1 7 Camshaft 1 For installation reverse the removal proce dure M M M 1 1 2 2 4 4 7 3 1 1 2 2 5 E E E T R 7 Nm 0 7 m kg 5 1 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib 6 M M New YamahaR125 COM ...

Page 190: ...sive wear pit ting scratches Replace or check the lubri cation system 3 Measure Rocker arm inside diameter a Out of specification Replace 4 Measure Rocker arm shaft outside diameter a Out of specification Replace Camshaft lobe dimensions Intake A 30 225 30 325 mm 1 1900 1 1939 in Limit 30 125 mm 1 1860 in Intake B 25 127 25 227 mm 0 9893 0 9932 in Limit 25 027 mm 0 9853 in Exhaust A 30 232 30 332 ...

Page 191: ...s a and hole b are positioned as shown in the illustra tion 4 Install Rocker arms Rocker arm shafts 1 NOTE Make sure that the cutout a in each rocker arm shaft is facing downward as shown in the illustration Make sure the rocker arm shafts intake and exhaust are completely pushed into the cylin der head Rocker arm to rocker arm shaft clearance 0 009 0 034 mm 0 0004 0 0013 in Limit 0 074 mm 0 0029 ...

Page 192: ...DER HEAD on page 5 7 Rocker arms Camshaft Refer to CAMSHAFT on page 5 14 1 Valve cotter 8 2 Upper spring seat 4 3 Valve spring 4 4 Intake valve 2 5 Exhaust valve 2 6 Valve stem seal 4 7 Lower spring seat 4 8 Valve guide 4 For installation reverse the removal proce dure New New New New M M M M M M M 1 2 3 6 7 8 1 2 3 6 7 8 1 2 3 6 7 8 1 2 3 6 7 8 5 5 4 4 YamahaR125 COM ...

Page 193: ...NOTE Remove the valve cotters by compressing the valve spring with the valve spring compressor and the valve spring compressor attachment 2 3 Remove Upper spring seat 1 Valve spring 2 Valve 3 Valve stem seal 4 Lower spring seat 5 NOTE Identify the position of each part very carefully so that it can be reinstalled in its original place EAS24290 CHECKING THE VALVES AND VALVE GUIDES The following pro...

Page 194: ...lve guide clearance NOTE After replacing the valve guide reface the valve seat Valve stem to valve guide clear ance intake 0 010 0 037 mm 0 0004 0 0015 in Limit 0 080 mm 0 0032 in Valve stem to valve guide clear ance exhaust 0 025 0 052 mm 0 0010 0 0020 in Limit 0 100 mm 0 0039 in Valve guide position intake 17 0 17 4 mm 0 669 0 685 in Valve guide position exhaust 14 0 14 4 mm 0 551 0 567 in a Val...

Page 195: ... seats 1 Eliminate Carbon deposits from the valve face and valve seat 2 Check Valve seat Pitting wear Replace the cylinder head 3 Measure Valve seat width C a Out of specification Replace the cylinder head a Apply Mechanic s blueing dye Dykem b onto the valve face b Install the valve into the cylinder head c Press the valve through the valve guide and onto the valve seat to make a clear impres sio...

Page 196: ...s lightly tap the valve seat while rotating the valve back and forth be tween your hands e Apply a fine lapping compound to the valve face and repeat the above steps f After every lapping procedure be sure to clean off all of the lapping compound from the valve face and valve seat g Apply Mechanic s blueing dye Dykem b onto the valve face h Install the valve into the cylinder head i Press the valv...

Page 197: ...he recommended lubricant 3 Install Lower spring seat 1 Valve stem seal 2 Free length intake 41 71 mm 1 64 in Limit 39 62 mm 1 56 in Free length exhaust 41 71 mm 1 64 in Limit 39 62 mm 1 56 in Installed compression spring force intake 140 162 N 31 47 36 42 lbf 14 28 16 52 kgf Installed compression spring force exhaust 140 162 N 31 47 36 42 lbf 14 28 16 52 kgf Installed length intake 35 30 mm 1 39 i...

Page 198: ...ers by compressing the valve spring with the valve spring compressor and the valve spring compressor attachment 2 5 To secure the valve cotters onto the valve stem lightly tap the valve tip with a soft face hammer CAUTION ECA13800 Hitting the valve tip with excessive force could damage the valve b Smaller pitch Valve spring compressor 90890 04019 YM 04019 Valve spring compressor attach ment 90890 ...

Page 199: ...arks Cylinder head Refer to CYLINDER HEAD on page 5 7 1 Cylinder 1 2 Cylinder gasket 1 3 Dowel pin 2 4 Piston pin clip 2 5 Piston pin 1 6 Piston 1 7 Top ring 1 8 2nd ring 1 9 Oil ring 1 For installation reverse the removal proce dure E E E E New New New New T R 7 Nm 0 7 m kg 5 1 ft Ib 6 5 4 7 8 4 2 3 1 3 9 YamahaR125 COM ...

Page 200: ... Top ring 2nd ring Oil ring NOTE When removing a piston ring open the end gap with your fingers and lift the other side of the ring over the piston crown EAS24390 CHECKING THE CYLINDER AND PISTON 1 Check Piston wall Cylinder wall Vertical scratches Replace the cylinder and replace the piston and piston rings as a set 2 Measure Piston to cylinder clearance a Measure cylinder bore C with the cylinde...

Page 201: ...n ring side clearance eliminate any carbon deposits from the piston ring grooves and piston rings 2 Install Piston ring into the cylinder NOTE Level the piston ring into the cylinder with the piston crown C maximum of D1 D2 T maximum of D1 or D2 maximum of D5 or D6 R maximum of D1 D3 or D5 minimum of D2 D4 or D6 b 5 0 mm 0 20 in from the bottom edge of the piston Piston Diameter D 51 962 51 985 mm...

Page 202: ...EAS24450 INSTALLING THE PISTON AND CYLINDER 1 Install Top ring 1 2nd ring 2 Oil ring expander 3 Lower oil ring rail 4 Upper oil ring rail 5 NOTE Be sure to install the piston rings so that the manufacturer marks or numbers face up Piston ring Top ring End gap installed 0 10 0 25 mm 0 0039 0 0098 in Limit 0 50 mm 0 0197 in 2nd ring End gap installed 0 10 0 25 mm 0 0039 0 0098 in Limit 0 60 mm 0 023...

Page 203: ...bricate Piston Piston rings Cylinder with the recommended lubricant 4 Offset Piston ring end gaps 5 Install Dowel pins Cylinder head gasket Cylinder 1 NOTE While compressing the piston rings with one hand install the cylinder with the other hand Pass the timing chain and timing chain guide intake side through the timing chain cavity Recommended lubricant Engine oil New 3 2 1 a New a Top ring b Upp...

Page 204: ...er 1 Disconnect 2 Crankshaft position sensor coupler 1 Disconnect 3 Neutral switch lead connector 1 Disconnect 4 Timing mark accessing screw 1 5 Crankshaft end accessing screw 1 6 Generator cover 1 7 Generator cover gasket 1 8 Dowel pin 2 9 Crankshaft position sensor 1 10 Stator coil 1 11 Generator rotor 1 3 LS LS E E T R 10 Nm 1 0 m kg 7 2 ft Ib T R 10 Nm 1 0 m kg 7 2 ft Ib T R 14 Nm 1 4 m kg 10 ...

Page 205: ...arter clutch assembly 1 For installation reverse the removal proce dure Removing the generator and starter clutch Order Job Parts to remove Q ty Remarks 3 LS LS E E T R 10 Nm 1 0 m kg 7 2 ft Ib T R 10 Nm 1 0 m kg 7 2 ft Ib T R 14 Nm 1 4 m kg 10 ft Ib T R 70 Nm 7 0 m kg 50 ft lb T R 10 Nm 1 0 m kg 7 2 ft Ib LT E E E 20 11 14 15 3 New New New 17 13 19 18 16 12 3 1 2 9 10 7 4 5 8 8 6 7 YamahaR125 COM...

Page 206: ...ft NOTE Make sure the flywheel puller is centered over the generator rotor EAS24560 REMOVING THE STARTER CLUTCH 1 Remove Starter clutch bolts 1 NOTE While holding the generator rotor 2 with the sheave holder 3 remove the starter clutch bolts Do not allow the sheave holder to touch the projection on the generator rotor EAS24570 CHECKING THE STARTER CLUTCH 1 Check Starter clutch rollers 1 Starter cl...

Page 207: ... be re placed EAS24600 INSTALLING THE STARTER CLUTCH 1 Install Starter clutch assembly Starter clutch bolts 1 NOTE While holding the generator rotor 2 with the sheave holder 3 tighten the starter clutch bolts Do not allow the sheave holder to touch the projection on the generator rotor Stake the end a of each starter clutch bolt EAS24500 INSTALLING THE GENERATOR 1 Install Woodruff key Generator ro...

Page 208: ...or rotor 3 Apply Sealant onto the crankshaft position sensor stator assembly lead grommet 4 Install Generator cover NOTE Tighten the generator cover bolts in the proper tightening sequence as shown Sheave holder 90890 01701 Primary clutch holder YS 01880 A Yamaha bond No 1215 90890 85505 Three Bond No 1215 T R Generator cover bolt 10 Nm 1 0 m kg 7 2 ft lb 1 3 2 3 11 5 1 6 7 8 4 2 10 9 YamahaR125 C...

Page 209: ...he starter motor Order Job Parts to remove Q ty Remarks Lower side cowlings Refer to GENERAL CHASSIS on page 4 1 1 Starter motor 1 2 Starter motor lead 1 Disconnect For installation reverse the removal proce dure 1 2 T R 10 Nm 1 0 m kg 7 2 ft Ib YamahaR125 COM ...

Page 210: ...r Job Parts to remove Q ty Remarks 1 O ring 1 2 Starter motor yoke 1 3 O ring 1 4 Commutator 1 5 Starter motor front cover brush holder set 1 6 Brush 2 7 Brush spring 2 For assembly reverse the disassembly pro cedure New New LS 4 2 5 1 6 7 7 6 3 YamahaR125 COM ...

Page 211: ...or and insulation Out of specification Replace the starter motor a Measure the armature assembly resistances with the pocket tester b If any resistance is out of specification re place the starter motor 5 Measure Brush length a Out of specification Replace the starter motor front cover brush holder set 6 Measure Brush spring force Out of specification Replace the brush springs as a set Limit 16 6 ...

Page 212: ...Damage wear Replace the starter motor front cover brush holder set EAS24800 ASSEMBLING THE STARTER MOTOR 1 Install Starter motor front cover brush holder set 1 Starter motor yoke 2 NOTE Align the marks a on the starter motor yoke and starter motor front cover brush holder set 2 a 1 YamahaR125 COM ...

Page 213: ...ing Refer to GENERAL CHASSIS on page 4 1 1 Clutch cable 1 Disconnect 2 Oil filter element cover 1 3 Oil filter element 1 4 Clutch cover 1 5 Clutch cover gasket 1 6 Dowel pin 2 7 Oil seal 1 For installation reverse the removal proce dure T R 10 Nm 1 0 m kg 7 2 ft Ib 1 LS New 7 New New LS T R 10 Nm 1 0 m kg 7 2 ft Ib T R 10 Nm 1 0 m kg 7 2 ft Ib 4 6 6 5 2 6 4 3 E YamahaR125 COM ...

Page 214: ...plate 1 1 8 Clutch plate 4 9 Friction plate 3 Green 3 10 Friction plate 2 1 11 Clutch damper spring 1 12 Clutch damper spring seat 1 13 Clutch boss nut 1 14 Lock washer 1 15 Clutch boss 1 16 Thrust washer 1 17 Clutch housing 1 New T R 12 Nm 1 2 m kg 8 7 ft Ib T R 8 Nm 0 8 m kg 5 8 ft Ib T R 70 Nm 7 0 m kg 50 ft lb E E 10 4 4 8 9 9 8 8 9 8 7 E 6 4 5 3 2 1 11 12 13 14 15 16 17 18 YamahaR125 COM ...

Page 215: ...reverse the removal proce dure Removing the clutch Order Job Parts to remove Q ty Remarks New T R 12 Nm 1 2 m kg 8 7 ft Ib T R 8 Nm 0 8 m kg 5 8 ft Ib T R 70 Nm 7 0 m kg 50 ft lb E E 10 4 4 8 9 9 8 8 9 8 7 E 6 4 5 3 2 1 11 12 13 14 15 16 17 18 YamahaR125 COM ...

Page 216: ... push lever Order Job Parts to remove Q ty Remarks 1 Clutch push lever 1 2 Clutch push lever spring 1 3 Circlip 1 4 Oil seal 1 5 Bearing 1 For installation reverse the removal proce dure New New LS E E 1 2 3 4 5 YamahaR125 COM ...

Page 217: ...NG THE CLUTCH PLATES The following procedure applies to all of the clutch plates 1 Check Clutch plate Damage Replace the clutch plates as a set 2 Measure Clutch plate warpage with a surface plate and thickness gauge 1 Out of specification Replace the clutch plates as a set Universal clutch holder 90890 04086 YM 91042 Friction plate 1 thickness 2 90 3 10 mm 0 114 0 122 in Wear limit 2 80 mm 0 110 i...

Page 218: ... the bearing and clutch housing EAS25160 CHECKING THE CLUTCH BOSS 1 Check Clutch boss splines Damage pitting wear Replace the clutch boss NOTE Pitting on the clutch boss splines will cause er ratic clutch operation EAS25170 CHECKING THE PRESSURE PLATE 1 Check Pressure plate Cracks damage Replace EAS5D71013 CHECKING THE CLUTCH PUSH LEVER AND SHORT CLUTCH PUSH ROD 1 Check Clutch push lever Short clu...

Page 219: ...E CLUTCH 1 Install Conical spring washer 1 NOTE Install the conical spring washer as shown in the illustration 2 Install Clutch housing Thrust washer 1 NOTE Be sure to install the thrust washer so that its sharp edge a is facing away from the clutch boss 3 Install Clutch boss 1 Lock washer 2 Clutch boss nut NOTE Lubricate the clutch boss nut threads and lock washer mating surfaces with engine oil ...

Page 220: ... stages and in a crisscross pattern 9 Adjust Clutch mechanism free play a Check that projection a on the clutch push lever 1 aligns with mark b shown on the crankcase in the illustration by pushing the clutch push lever manually in direction c un til it stops b If projection a is not aligned with mark b align them as follows Loosen the locknut 2 With the clutch push lever fully pushed in di rectio...

Page 221: ...s in the proper tight ening sequence as shown 12 Adjust Clutch cable free play Refer to ADJUSTING THE CLUTCH CABLE FREE PLAY on page 3 12 Installed depth of oil seal a 1 4 1 9 mm 0 055 0 075 in T R Clutch cover bolt 10 Nm 1 0 m kg 7 2 ft lb 2 3 1 a 11 2 12 10 9 8 1 7 3 13 6 5 4 YamahaR125 COM ...

Page 222: ...utch housing Refer to CLUTCH on page 5 38 Balancer drive gear Refer to BALANCER GEAR on page 5 53 1 Oil baffle plate 1 2 Oil pump assembly 1 3 Oil pump drive gear 1 For installation reverse the removal proce dure T R 4 Nm 0 4 m kg 2 9 ft Ib T R 10 Nm 1 0 m kg 7 2 ft Ib LT LT 2 3 1 YamahaR125 COM ...

Page 223: ...er Job Parts to remove Q ty Remarks 1 Oil pump housing cover 1 2 Pin 1 3 Oil pump driven gear 1 4 Oil pump inner rotor 1 5 Oil pump outer rotor 1 6 Oil pump housing 1 For assembly reverse the disassembly pro cedure 1 5 2 4 6 3 E E YamahaR125 COM ...

Page 224: ... OIL PUMP 1 Lubricate Oil pump inner rotor Oil pump outer rotor Oil pump driven gear with the recommended lubricant 2 Install Oil pump outer rotor Oil pump inner rotor 1 Oil pump driven gear Pin 2 NOTE When installing the inner rotor align the pin 2 in the oil pump shaft with the groove a in the in ner rotor 1 1 Inner rotor 2 Outer rotor 3 Oil pump housing Inner rotor to outer rotor tip clearance ...

Page 225: ...HECKING THE OIL PUMP on page 5 49 EAS25020 INSTALLING THE OIL PUMP 1 Install Oil pump assembly CAUTION ECA5D71021 After tightening the screws make sure the oil pump turns smoothly T R Oil pump assembly screw 4 Nm 0 4 m kg 2 9 ft lb 2 a 1 YamahaR125 COM ...

Page 226: ...arks Clutch housing Refer to CLUTCH on page 5 38 Shift arm Refer to ENGINE REMOVAL on page 5 1 1 Shift shaft 1 2 Circlip 1 3 Shift shaft spring 1 4 Stopper lever 1 5 Stopper lever spring 1 6 Oil seal 1 For installation reverse the removal proce dure LT T R 10 Nm 1 0 m kg 7 2 ft Ib 5 1 3 6 4 2 New E LS YamahaR125 COM ...

Page 227: ...er lever spring Damage wear Replace EAS25450 INSTALLING THE SHIFT SHAFT 1 Install Stopper lever 1 Stopper lever spring 2 NOTE Install the stopper lever spring as shown in the illustration Hook the ends of the stopper lever spring onto the stopper lever and the crankcase boss 3 Mesh the stopper lever with the shift drum seg ment assembly 2 Install Shift shaft 1 NOTE Hook the end of the shift shaft ...

Page 228: ...UTCH on page 5 38 1 Primary drive gear nut 1 2 Balancer driven gear nut 1 3 Washer 1 4 Primary drive gear 1 5 Balancer drive gear 1 6 Straight key 1 7 Lock washer 1 8 Balancer driven gear 1 9 Straight key 1 10 Spacer 1 For installation reverse the removal proce dure 1 3 4 5 6 9 7 8 2 10 T R 50 Nm 5 0 m kg 36 ft Ib New T R 60 Nm 6 0 m kg 43 ft Ib YamahaR125 COM ...

Page 229: ...ry drive gear Refer to CHECKING THE PRIMARY DRIVE GEAR on page 5 43 EAS5D71021 INSTALLING THE PRIMARY DRIVE GEAR AND BALANCER GEARS 1 Install Balancer driven gear 1 Lock washer Balancer drive gear 2 Primary drive gear Washer 3 Balancer driven gear nut Primary drive gear nut NOTE Align the punch mark a in the balancer drive gear 2 with the punch mark b in the balancer driven gear 1 Be sure to insta...

Page 230: ...lace the aluminum plate b between the bal ancer drive gear 3 and the balancer driven gear 4 and then tighten the primary drive gear nut 3 Bend the lock washer tab along a flat side of the nut a 4 1 3 3 2 b 4 YamahaR125 COM ...

Page 231: ...t shaft Refer to SHIFT SHAFT on page 5 51 Starter motor Refer to ELECTRIC STARTER on page 5 34 Balancer gears Refer to BALANCER GEAR on page 5 53 Generator rotor Refer to GENERATOR AND STARTER CLUTCH on page 5 29 1 Timing chain guide intake side 1 2 Chain cover 1 3 Timing chain 1 4 Engine oil drain plug 1 5 Spring 1 8 9 8 New New T R 20 Nm 2 0 m kg 14 ft Ib T R 10 Nm 1 0 m kg 7 2 ft Ib T R 10 Nm 1...

Page 232: ...or installation reverse the removal proce dure Separating the crankcase Order Job Parts to remove Q ty Remarks 8 9 8 New New T R 20 Nm 2 0 m kg 14 ft Ib T R 10 Nm 1 0 m kg 7 2 ft Ib T R 10 Nm 1 0 m kg 7 2 ft Ib T R 10 Nm 1 0 m kg 7 2 ft Ib 1 3 2 4 5 6 7 11 11 10 12 T R 10 Nm 1 0 m kg 7 2 ft Ib T R 32 Nm 3 2 m kg 23 ft Ib LS YamahaR125 COM ...

Page 233: ... ty Remarks Crankshaft Balancer Refer to CRANKSHAFT on page 5 61 Transmission Refer to TRANSMISSION on page 5 64 1 Oil seal 1 2 Bearing retainer 1 3 Bearing 7 For installation reverse the removal proce dure LT E E E 2 1 3 3 3 3 3 3 3 T R 7 Nm 0 7 m kg 5 1 ft Ib LS YamahaR125 COM ...

Page 234: ... EAS25580 CHECKING THE CRANKCASE 1 Thoroughly wash the crankcase halves in a mild solvent 2 Thoroughly clean all the gasket surfaces and crankcase mating surfaces 3 Check Crankcase Cracks damage Replace Oil delivery passages Obstruction Blow out with compressed air EAS5D71033 CHECKING THE TIMING CHAIN AND TIMING CHAIN GUIDE 1 Check Timing chain Damage stiffness Replace the timing chain and camshaf...

Page 235: ...e into contact with the oil gallery 3 Install Right crankcase NOTE Turn the shift drum segment 1 to the position shown in the illustration In this position the shift drum segment teeth will not contact the crank case during crankcase installation 4 Install Crankcase bolts NOTE Tighten each bolt 1 4 of a turn at a time in stag es and in the proper sequence as shown M6 70 mm 7 9 11 M6 55 mm 14 15 M6...

Page 236: ...emoving the crankshaft and balancer Order Job Parts to remove Q ty Remarks Crankcase Separate Refer to CRANKCASE on page 5 56 1 Balancer 1 2 Crankshaft 1 For installation reverse the removal proce dure New New 1 2 LS LS E E YamahaR125 COM ...

Page 237: ...t of specification Replace the crank shaft 3 Measure Crankshaft width Out of specification Replace the crank shaft 4 Check Crankshaft sprocket Damage wear Replace the crankshaft Bearing Cracks damage wear Replace the crank shaft 5 Check Crankshaft journal Scratches wear Replace the crankshaft Crankshaft journal oil passage Obstruction Blow out with compressed air EAS5D71036 INSTALLING THE CRANKSHA...

Page 238: ...t top dead center TDC with one hand while turning the nut of the crankshaft installer bolt with the other Turn the crankshaft installer bolt until the crankshaft bot toms against the bearing Crankshaft installer pot 90890 01274 Installing pot YU 90058 Crankshaft installer bolt 90890 01275 Bolt YU 90060 Adapter M12 90890 01278 Adapter 3 YU 90063 Spacer crankshaft installer 90890 04081 Pot spacer YM...

Page 239: ...Remarks Crankcase Separate Refer to CRANKCASE on page 5 56 1 Shift fork guide bar 1 2 Spring 2 3 Shift drum assembly 1 4 Shift fork R 1 5 Shift fork C 1 6 Shift fork L 1 7 Drive axle assembly 1 8 Main axle assembly 1 9 Long clutch push rod 1 For installation reverse the removal proce dure E 7 8 9 2 1 2 3 4 5 6 E E E E YamahaR125 COM ...

Page 240: ... Parts to remove Q ty Remarks 1 2nd pinion gear 1 2 6th pinion gear 1 3 3rd 4th pinion gear 1 4 Circlip 1 5 Toothed washer 1 6 5th pinion gear 1 7 Main axle 1st pinion gear 1 For assembly reverse the disassembly pro cedure M 2 1 4 5 3 6 7 M M YamahaR125 COM ...

Page 241: ...asher 1 2 2nd wheel gear 1 3 6th wheel gear 1 4 Washer 1 5 1st wheel gear 1 6 Spacer 1 7 5th wheel gear 1 8 Circlip 1 9 Toothed washer 1 10 4th wheel gear 1 11 3rd wheel gear 1 12 Drive axle 1 For assembly reverse the disassembly pro cedure 2 1 9 10 7 5 6 11 8 4 12 3 M M M M YamahaR125 COM ...

Page 242: ...e shift forks and shift fork guide bar as a set EAS26270 CHECKING THE SHIFT DRUM ASSEMBLY 1 Check Shift drum groove Damage scratches wear Replace the shift drum assembly Shift drum segment 1 Damage wear Replace the shift drum as sembly Shift drum bearing 2 Damage pitting Replace the shift drum as sembly EAS26290 CHECKING THE TRANSMISSION 1 Measure Main axle runout with a centering device and dial ...

Page 243: ... bending limit Out of specification Replace the long clutch push rod EAS29020 ASSEMBLING THE MAIN AXLE AND DRIVE AXLE 1 Install Toothed washer 1 Circlip 2 NOTE Be sure to install the circlip so that its sharp edge a is facing away from the toothed wash er and gear Be sure the circlip ends b are positioned at the axle spline groove c 2 Install 2nd pinion gear 1 NOTE Press the 2nd pinion gear into t...

Page 244: ...side of the engine and be in the following sequence R C L 2 Check Transmission Rough movement Repair NOTE Apply engine oil to each gear and bearing thor oughly Before assembling the crankcase make sure that the transmission is in neutral and that the gears turn freely 1 2 3 5 4 YamahaR125 COM ...

Page 245: ... 3 INSTALLING THE RADIATOR 6 3 THERMOSTAT 6 4 CHECKING THE THERMOSTAT 6 5 INSTALLING THE THERMOSTAT 6 5 WATER PUMP 6 6 DISASSEMBLING THE WATER PUMP 6 8 CHECKING THE WATER PUMP 6 8 ASSEMBLING THE WATER PUMP 6 8 INSTALLING THE WATER PUMP 6 9 YamahaR125 COM ...

Page 246: ... tank Refer to FUEL TANK on page 7 1 1 Coolant reservoir breather hose 1 2 Coolant reservoir hose 1 3 Coolant reservoir 1 4 Water pump breather hose 1 5 Radiator outlet hose 1 6 Radiator fan coupler 1 Disconnect 7 Radiator inlet hose 1 Disconnect 8 Radiator cap 1 9 Radiator 1 10 Radiator fan 1 T R 10 Nm 1 0 m kg 7 2 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib 11 6 8 7 10 5 3 2 1 4 9 T R 8 Nm 0 8 m kg 5 8 ft...

Page 247: ... For installation reverse the removal proce dure Removing the radiator Order Job Parts to remove Q ty Remarks T R 10 Nm 1 0 m kg 7 2 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib 11 6 8 7 10 5 3 2 1 4 9 T R 8 Nm 0 8 m kg 5 8 ft Ib YamahaR125 COM ...

Page 248: ...ere is no drop in pressure 4 Check Radiator fan Damage Replace Malfunction Check and repair Refer to COOLING SYSTEM on page 8 25 EAS26400 INSTALLING THE RADIATOR 1 Fill Cooling system with the specified amount of the recom mended coolant Refer to CHANGING THE COOLANT on page 3 15 2 Check Cooling system Leaks Repair or replace any faulty part 3 Measure Radiator cap opening pressure Below the specif...

Page 249: ... upper side cowling Refer to GENERAL CHASSIS on page 4 1 Fuel tank Refer to FUEL TANK on page 7 1 1 Coolant temperature sensor coupler 1 Disconnect 2 Coolant temperature sensor 1 3 Thermostat cover 1 4 Thermostat 1 5 Radiator inlet hose 1 For installation reverse the removal proce dure T R 10 Nm 1 0 m kg 7 2 ft Ib T R 18 Nm 1 8 m kg 13 ft Ib New 1 2 5 3 4 YamahaR125 COM ...

Page 250: ... EAS26480 INSTALLING THE THERMOSTAT 1 Install Thermostat NOTE Install the thermostat with its breather hole a facing up 2 Install Copper washer Coolant temperature sensor CAUTION ECA5D71004 Use extreme care when handling the coolant temperature sensor Replace any part that was dropped or subjected to a strong im pact 3 Fill Cooling system with the specified amount of the recom mended coolant Refer...

Page 251: ...ain Refer to CHANGING THE COOLANT on page 3 15 Left upper side cowling Refer to GENERAL CHASSIS on page 4 1 Fuel tank Refer to FUEL TANK on page 7 1 1 Radiator outlet hose 1 2 Water pump breather hose 1 3 Cylinder head breather hose 1 Disconnect 4 Radiator bolt 1 5 Water pump assembly 1 For installation reverse the removal proce dure T R 10 Nm 1 0 m kg 7 2 ft Ib New LS New 4 5 2 1 3 LS T R 10 Nm 1...

Page 252: ... gasket 1 4 Impeller shaft retainer 1 5 Impeller shaft 1 6 Water pump housing plate 1 7 Water pump housing gasket 1 8 Water pump seal 1 9 Bearing 1 10 Water pump housing 1 For assembly reverse the disassembly pro cedure New New New LS T R 10 Nm 1 0 m kg 7 2 ft Ib T R 10 Nm 1 0 m kg 7 2 ft Ib T R 10 Nm 1 0 m kg 7 2 ft Ib 1 2 3 10 8 5 9 4 6 7 LT YamahaR125 COM ...

Page 253: ...HE WATER PUMP 1 Install Water pump seal 1 into the water pump housing 2 CAUTION ECA14080 Never lubricate the water pump seal surface with oil or grease NOTE Install the water pump seal with the special tools Install the water pump seal with the special tools to the specified depth as shown in the il lustration 2 Lubricate Water pump seal lip 3 Install Water pump housing gasket 1 2 1 2 1 New Mechan...

Page 254: ...TER PUMP 1 Install Water pump assembly 1 O rings 2 NOTE Align the projection a on the impeller shaft with the slit b on the camshaft sprocket bolt Lubricate the O rings with a thin coat of lithium soap based grease 2 Fill Cooling system with the specified amount of the recom mended coolant Refer to CHANGING THE COOLANT on page 3 15 3 Check Cooling system Leaks Repair or replace the faulty part 4 M...

Page 255: ... 2 INSTALLING THE FUEL HOSE 7 2 CHECKING THE FUEL PRESSURE 7 2 THROTTLE BODY 7 4 REMOVING THE THROTTLE BODY 7 6 CHECKING THE FUEL INJECTOR 7 6 CHECKING THE THROTTLE BODY 7 6 INSTALLING THE THROTTLE BODY 7 6 AIR INDUCTION SYSTEM 7 9 CHECKING THE AIR INDUCTION SYSTEM 7 12 YamahaR125 COM ...

Page 256: ...L CHASSIS on page 4 1 1 Fuel pump coupler 1 Disconnect 2 Fuel sender coupler 1 Disconnect 3 Fuel hose connector cover 1 4 Fuel hose 1 Disconnect 5 Fuel overflow hose 1 6 Bracket 1 7 Fuel tank 1 For installation reverse the removal proce dure 2 1 6 5 3 4 7 T R 10 Nm 1 0 m kg 7 2 ft Ib T R 10 Nm 1 0 m kg 7 2 ft Ib YamahaR125 COM ...

Page 257: ...racks damage Replace the fuel tank EAS5D71043 INSTALLING THE FUEL HOSE 1 Install Fuel hose Fuel hose connector cover CAUTION ECA5D71032 When installing the fuel hose make sure that it is securely connected and that the fuel hose connector cover is in the correct posi tion otherwise the fuel hose will not be prop erly installed NOTE Wipe up any fuel remaining in the recess a in the fuel pump with a...

Page 258: ...el pressure Faulty Replace the fuel tank with fuel pump e Connect the fuel hose and install the fuel hose connector cover Refer to INSTALLING THE FUEL HOSE on page 7 2 Pressure gauge 90890 03153 YU 03153 Fuel pressure adapter 90890 03181 Output pressure 250 0 kPa 36 3 psi 2 50 kgf cm 1 2 2 4 3 YamahaR125 COM ...

Page 259: ...noid coupler 1 Disconnect 4 Fuel injector 1 5 Fuel injector gasket 1 6 Throttle body sensor assembly coupler 1 Disconnect 7 Throttle cable 1 Disconnect 8 Throttle body joint clamp screw 2 Loosen 9 Throttle body 1 CAUTION ECA5D71015 The throttle body should not be disas sembled 10 Throttle body joint 1 LT 1 2 3 5 4 6 7 9 8 10 8 11 T R 12 Nm 1 2 m kg 8 7 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib T R 2 Nm 0 ...

Page 260: ...se the removal proce dure Removing the throttle body Order Job Parts to remove Q ty Remarks LT 1 2 3 5 4 6 7 9 8 10 8 11 T R 12 Nm 1 2 m kg 8 7 ft Ib T R 7 Nm 0 7 m kg 5 1 ft Ib T R 2 Nm 0 2 m kg 1 4 ft Ib LS New New E T R 10 Nm 1 0 m kg 7 2 ft Ib YamahaR125 COM ...

Page 261: ...gs in the area under where it will be removed 3 Remove Throttle body CAUTION ECA5D71016 Do not remove the throttle body sensor as sembly 1 from the throttle body EAS5D71028 CHECKING THE FUEL INJECTOR 1 Check Fuel injector Damage Replace EAS26990 CHECKING THE THROTTLE BODY 1 Check Throttle body Cracks damage Replace the throttle body 2 Check Fuel passages Obstruction Clean a Wash the throttle body ...

Page 262: ...1005 When installing the fuel hose make sure that it is securely connected and that the fuel hose connector cover on the fuel hose is in the correct position otherwise the fuel hose will not be properly installed NOTE Install the fuel hose securely onto the fuel pump until a distinct click is heard To install the fuel hose onto the fuel pump slide the fuel hose connector cover 1 on the end of the ...

Page 263: ...THROTTLE BODY 7 8 YamahaR125 COM ...

Page 264: ...AIR INDUCTION SYSTEM 7 9 EAS27040 AIR INDUCTION SYSTEM 1 2 3 YamahaR125 COM ...

Page 265: ...DUCTION SYSTEM 7 10 1 Air induction system hose air filter case to reed valve assembly 2 Air induction system reed valve assembly 3 Air induction system hose reed valve assembly to exhaust pipe YamahaR125 COM ...

Page 266: ...er to GENERAL CHASSIS on page 4 1 Fuel tank Refer to FUEL TANK on page 7 1 1 Air induction system hose reed valve assembly to exhaust pipe 1 2 Air induction system reed valve assembly 1 3 Air induction system hose air filter case to reed valve assembly 1 For installation reverse the removal proce dure T R 10 Nm 1 0 m kg 7 2 ft Ib 1 3 2 YamahaR125 COM ...

Page 267: ...ature for burning the un burned exhaust gases is approximately 600 to 700 C 1112 to 1292 F 1 Check Hoses Loose connections Connect properly Cracks damage Replace Pipes Cracks damage Replace 2 Check Air induction system reed valve assembly op eration a Blow air into the pipe 1 of the air induction system reed valve assembly and check that it comes out from the pipe 2 b Blow air into the pipe 2 of t...

Page 268: ...AIR INDUCTION SYSTEM 7 13 YamahaR125 COM ...

Page 269: ...GHTING SYSTEM 8 15 CIRCUIT DIAGRAM 8 15 TROUBLESHOOTING 8 17 SIGNALING SYSTEM 8 19 CIRCUIT DIAGRAM 8 19 TROUBLESHOOTING 8 21 COOLING SYSTEM 8 25 CIRCUIT DIAGRAM 8 25 TROUBLESHOOTING 8 27 FUEL INJECTION SYSTEM 8 29 CIRCUIT DIAGRAM 8 29 ECU SELF DIAGNOSTIC FUNCTION 8 31 SELF DIAGNOSTIC FUNCTION TABLE 8 32 TROUBLESHOOTING METHOD 8 34 DIAGNOSTIC MODE 8 35 TROUBLESHOOTING DETAILS 8 41 FUEL PUMP SYSTEM ...

Page 270: ... 8 68 CHECKING THE IGNITION SPARK GAP 8 69 CHECKING THE CRANKSHAFT POSITION SENSOR 8 69 CHECKING THE LEAN ANGLE SENSOR 8 69 CHECKING THE STARTER MOTOR OPERATION 8 70 CHECKING THE STATOR COIL 8 70 CHECKING THE RECTIFIER REGULATOR 8 71 CHECKING THE HORN 8 71 CHECKING THE FUEL SENDER 8 72 CHECKING THE SPEED SENSOR 8 72 CHECKING THE RADIATOR FAN MOTOR 8 72 CHECKING THE COOLANT TEMPERATURE SENSOR 8 73 ...

Page 271: ...YamahaR125 COM ...

Page 272: ...RNESS SUB WIRE HARNESS B W Dg BLACK Ch Y L G W Sb Ch Dg BLACK B W Sb G W Y L B WIRE HARNESS SUB WIRE HARNESS SUB WIRE HARNESS R B Y R G R Gy B OFF ON PASS R Gy B W W W W R W O Br Br L R Y Dg Dg Br L R B Br L R W R Gy R Gy R R R B P W P W Gy B Gy B Br W Br W Y Y G R O B Y R O O B R W G R Gy B Gy B Gy R Y G Y G Y W G W B W Gy Gy R L Y Br L L B B R B B Br Br W Br W Br B B R B L W R W Sb W P B Ch Dg G...

Page 273: ... 2 2 Crankshaft position sensor 4 Main fuse 5 Main switch 8 Sidestand switch 9 Battery 17 Engine stop switch 23 Lean angle sensor 25 ECU engine control unit 26 Ignition coil 27 Spark plug 64 Ignition fuse YamahaR125 COM ...

Page 274: ...Refill battery fluid Clean the battery terminals Recharge or replace the battery 3 Check the spark plug Refer to CHECKING THE SPARK PLUG on page 3 7 Re gap or replace the spark plug 4 Check the ignition spark gap Refer to CHECKING THE IGNI TION SPARK GAP on page 8 69 Ignition system is OK 5 Check the spark plug cap Refer to CHECKING THE SPARK PLUG CAP on page 8 68 Replace the spark plug cap 6 Chec...

Page 275: ...switch is faulty Replace the right handlebar switch 10 Check the sidestand switch Refer to CHECKING THE SWITCHES on page 8 59 Replace the sidestand switch 11 Check the lean angle sensor Refer to CHECKING THE LEAN ANGLE SENSOR on page 8 69 Replace the lean angle sensor 12 Check the entire ignition system wiring Refer to CIRCUIT DIAGRAM on page 8 1 Properly connect or repair the ignition sys tem wir...

Page 276: ...S SUB WIRE HARNESS B W Dg BLACK Ch Y L G W Sb Ch Dg BLACK B W Sb G W Y L B WIRE HARNESS SUB WIRE HARNESS SUB WIRE HARNESS R B Y R G R Gy B OFF ON PASS R Gy B W W W W R W O Br Br L R Y Dg Dg Br L R B Br L R W R Gy R Gy R R R B P W P W Gy B Gy B Br W Br W Y Y G R O B Y R O O B R W G R Gy B Gy B Gy R Y G Y G Y W G W B W Gy Gy R L Y Br L L B B R B B Br Br W Br W Br B B R B L W R W Sb W P B Ch Dg G Y R...

Page 277: ...Main fuse 5 Main switch 7 Clutch switch 8 Sidestand switch 9 Battery 10 Starter relay 11 Starter motor 12 Starting circuit cut off relay 13 Diode 14 Neutral switch 16 Start switch 17 Engine stop switch 64 Ignition fuse YamahaR125 COM ...

Page 278: ... pulled to the handlebar the clutch switch is closed and the sidestand is up the sidestand switch is closed The starting circuit cut off relay prevents the starter motor from operating when neither of these condi tions has been met In this instance the starting circuit cut off relay is open so current cannot reach the starter motor When at least one of the above conditions has been met the startin...

Page 279: ...ER IS PULLED TO THE HANDLEBAR AND THE SIDESTAND IS UP 1 Battery 2 Main fuse 3 Main switch 4 Ignition fuse 5 Engine stop switch 6 Starting circuit cut off relay 7 Clutch switch 8 Sidestand switch 9 Diode 10 Neutral switch 11 Start switch 12 Starter relay 13 Starter motor YamahaR125 COM ...

Page 280: ...tery terminals Recharge or replace the battery 3 Check the starter motor operation Refer to CHECKING THE START ER MOTOR OPERATION on page 8 70 Starter motor is OK Perform the electric starting system troubleshooting starting with step 5 4 Check the starter motor Refer to CHECKING THE START ER MOTOR on page 5 36 Repair or replace the starter motor 5 Check the starting circuit cut off re lay Refer t...

Page 281: ...TCHES on page 8 59 Replace the neutral switch 11 Check the sidestand switch Refer to CHECKING THE SWITCHES on page 8 59 Replace the sidestand switch 12 Check the clutch switch Refer to CHECKING THE SWITCHES on page 8 59 Replace the clutch switch 13 Check the start switch Refer to CHECKING THE SWITCHES on page 8 59 The start switch is faulty Replace the right handlebar switch 14 Check the entire st...

Page 282: ...B Br L L Y W W W B R L B R R B R W R W R W L W B L W B R B R W OFF ON R Gy B W W W W Br Br L R Y Br L R B Br L R W R R L Y Br L L B B R B B Br B B R B L W R W Sb W R YR Y L B W B Sb W Y W O W Sb Y L G W Sb W Y W O W Sb Y L G W R B R R R W R L B L B L W R B L B L B B B W W R R B A A A B B B L B R W R B R R W L B R B R B Sb W P 13 1 2 3 4 5 8 7 9 10 11 12 43 44 66 65 64 14 6 15 16 17 R Sb W L B R B ...

Page 283: ...CHARGING SYSTEM 8 12 1 AC magneto 3 Rectifier regulator 4 Main fuse 9 Battery YamahaR125 COM ...

Page 284: ... CHARGING THE BATTERY on page 8 64 Refill battery fluid Clean the battery terminals Recharge or replace the battery 3 Check the stator coil Refer to CHECKING THE STATOR COIL on page 8 70 Replace the crankshaft position sen sor stator assembly 4 Check the rectifier regulator Refer to CHECKING THE RECTI FIER REGULATOR on page 8 71 Replace the rectifier regulator 5 Check the entire charging system wi...

Page 285: ...CHARGING SYSTEM 8 14 YamahaR125 COM ...

Page 286: ...E HARNESS B W Dg BLACK Ch Y L G W Sb Ch Dg BLACK B W Sb G W Y L B WIRE HARNESS SUB WIRE HARNESS SUB WIRE HARNESS R B Y R G R Gy B OFF ON PASS R Gy B W W W W R W O Br Br L R Y Dg Dg Br L R B Br L R W R Gy R Gy R R R B P W P W Gy B Gy B Br W Br W Y Y G R O B Y R O O B R W G R Gy B Gy B Gy R Y G Y G Y W G W B W Gy Gy R L Y Br L L B B R B B Br Br W Br W Br B B R B L W R W Sb W P B Ch Dg G Y R YR Y L B...

Page 287: ...unit 36 License plate light 37 Tail brake light 44 Headlight relay 46 Pass switch 47 Dimmer switch 51 Headlight low beam 52 Auxiliary light 54 Headlight high beam 58 Meter light 60 High beam indicator light 64 Ignition fuse 65 Headlight fuse 66 Signaling system fuse YamahaR125 COM ...

Page 288: ...ling system Refer to CHECKING THE FUS ES on page 8 63 Replace the fuse s 3 Check the battery Refer to CHECKING AND CHARGING THE BATTERY on page 8 64 Refill battery fluid Clean the battery terminals Recharge or replace the battery 4 Check the main switch Refer to CHECKING THE SWITCHES on page 8 59 Replace the main switch 5 Check the dimmer switch Refer to CHECKING THE SWITCHES on page 8 59 The dimm...

Page 289: ...TING SYSTEM 8 18 NG OK 8 Check the entire lighting system wiring Refer to CIRCUIT DIAGRAM on page 8 15 Properly connect or repair the lighting sys tem wiring Replace the ECU or meter assembly YamahaR125 COM ...

Page 290: ...RE HARNESS B W Dg BLACK Ch Y L G W Sb Ch Dg BLACK B W Sb G W Y L B WIRE HARNESS SUB WIRE HARNESS SUB WIRE HARNESS R B Y R G R Gy B OFF ON PASS R Gy B W W W W R W O Br Br L R Y Dg Dg Br L R B Br L R W R Gy R Gy R R R B P W P W Gy B Gy B Br W Br W Y Y G R O B Y R O O B R W G R Gy B Gy B Gy R Y G Y G Y W G W B W Gy Gy R L Y Br L L B B R B B Br Br W Br W Br B B R B L W R W Sb W P B Ch Dg G Y R YR Y L ...

Page 291: ...ail brake light 38 Rear right turn signal light 39 Rear left turn signal light 40 Front right turn signal light 41 Front left turn signal light 42 Turn signal relay 43 Horn 48 Horn switch 49 Turn signal switch 56 Multi function meter 57 Tachometer 61 Turn signal indicator light 62 Neutral indicator light 64 Ignition fuse 66 Signaling system fuse 67 Speed sensor YamahaR125 COM ...

Page 292: ...g sys tem Refer to CHECKING THE FUS ES on page 8 63 Replace the fuse s 2 Check the battery Refer to CHECKING AND CHARGING THE BATTERY on page 8 64 Refill battery fluid Clean the battery terminals Recharge or replace the battery 3 Check the main switch Refer to CHECKING THE SWITCHES on page 8 59 Replace the main switch 4 Check the entire signaling system wiring Refer to CIRCUIT DIAGRAM on page 8 19...

Page 293: ... switch 2 Check the rear brake light switch Refer to CHECKING THE SWITCHES on page 8 59 Replace the rear brake light switch 3 Check the entire signaling system wiring Refer to CIRCUIT DIAGRAM on page 8 19 Properly connect or repair the signaling system wiring Replace the tail brake light assembly 1 Check the turn signal light bulb and socket Refer to CHECKING THE BULBS AND BULB SOCKETS on page 8 6...

Page 294: ...em wiring Refer to CIRCUIT DIAGRAM on page 8 19 Properly connect or repair the signaling system wiring Replace the meter assembly 1 Check the fuel sender Refer to CHECKING THE FUEL SENDER on page 8 72 Replace the fuel sender 2 Check the entire signaling system wiring Refer to CIRCUIT DIAGRAM on page 8 19 Properly connect or repair the signaling system wiring Replace the meter assembly 1 Check the ...

Page 295: ...SIGNALING SYSTEM 8 24 YamahaR125 COM ...

Page 296: ... HARNESS B W Dg BLACK Ch Y L G W Sb Ch Dg BLACK B W Sb G W Y L B WIRE HARNESS SUB WIRE HARNESS SUB WIRE HARNESS R B Y R G R Gy B OFF ON PASS R Gy B W W W W R W O Br Br L R Y Dg Dg Br L R B Br L R W R Gy R Gy R R R B P W P W Gy B Gy B Br W Br W Y Y G R O B Y R O O B R W G R Gy B Gy B Gy R Y G Y G Y W G W B W Gy Gy R L Y Br L L B B R B B Br Br W Br W Br B B R B L W R W Sb W P B Ch Dg G Y R YR Y L B ...

Page 297: ...witch 6 Radiator fan motor fuse 9 Battery 22 Coolant temperature sensor 25 ECU engine control unit 32 Radiator fan motor relay 33 Radiator fan motor 59 Coolant temperature warning light 64 Ignition fuse 66 Signaling system fuse YamahaR125 COM ...

Page 298: ...place the battery 3 Check the main switch Refer to CHECKING THE SWITCHES on page 8 59 Replace the main switch 4 Check the radiator fan motor Refer to CHECKING THE RADIA TOR FAN MOTOR on page 8 72 Replace the radiator fan motor 5 Check the radiator fan motor relay Refer to CHECKING THE RE LAYS on page 8 66 Replace the radiator fan motor relay 6 Check the coolant temperature sen sor Refer to CHECKIN...

Page 299: ...COOLING SYSTEM 8 28 YamahaR125 COM ...

Page 300: ...UB WIRE HARNESS B W Dg BLACK Ch Y L G W Sb Ch Dg BLACK B W Sb G W Y L B WIRE HARNESS SUB WIRE HARNESS SUB WIRE HARNESS R B Y R G R Gy B OFF ON PASS R Gy B W W W W R W O Br Br L R Y Dg Dg Br L R B Br L R W R Gy R Gy R R R B P W P W Gy B Gy B Br W Br W Y Y G R O B Y R O O B R W G R Gy B Gy B Gy R Y G Y G Y W G W B W Gy Gy R L Y Br L L B B R B B Br Br W Br W Br B B R B L W R W Sb W P B Ch Dg G Y R YR...

Page 301: ...r temperature sensor 21 Throttle position sensor 22 Coolant temperature sensor 23 Lean angle sensor 24 Self diagnosis signal connector 25 ECU engine control unit 26 Ignition coil 27 Spark plug 28 FID fast idle solenoid 29 Fuel injector 30 Fuel pump 32 Radiator fan motor relay 33 Radiator fan motor 63 Engine trouble warning light 64 Ignition fuse 66 Signaling system fuse 67 Speed sensor YamahaR125 ...

Page 302: ...trouble warning light flashes when the start switch is being pushed to start the engine If a malfunction is detected in the system by the self diagnostic function the ECU provides an appro priate substitute characteristic operation and alerts the rider of the detected malfunction by illuminat ing the engine trouble warning light After the engine has been stopped the lowest fault code number is ind...

Page 303: ...from a sensor the ECU processes the specified values that are programmed for each sensor in order to provide the engine with alternate operating instructions that enable the engine to continue to operate or stop operating depending on the conditions Warning light indica tion ECU operation Fuel injection opera tion Vehicle operation Flashing Warning provided when unable to start engine Operation st...

Page 304: ...ted Able Able 22 Intake air tempera ture sensor open or short circuit Intake air temperature sensor open or short circuit detected Able Able 30 Lean angle sensor latch up detected No normal signal is received from the lean angle sensor Unable Unable 33 Ignition coil open circuit Primary lead of the ignition coil open circuit detected Unable Unable 39 Fuel injector Fuel injector open or short circu...

Page 305: ...er is displayed 5 Erase the malfunction history in the diagnos tic mode Refer to Sensor operation table Diagnostic code No 62 NOTE Setting the main switch to OFF will not erase the malfunction history The engine operation is not normal but the engine trouble warning light does not come on 1 Check the operation of the following sensors and actuators in the diagnostic mode Refer to Sensor operation ...

Page 306: ... normal mode 1 Set the main switch to OFF and the engine stop switch to 2 Disconnect the self diagnosis signal connector 1 and then connect the FI diagnostic tool 2 as shown 3 Set the main switch to ON and start the engine NOTE The coolant temperature and engine speed appear on the LCD of the FI diagnostic tool POWER LED green comes on If a malfunction is detected in the system the WARNING LED ora...

Page 307: ...agnostic mode DIAG 6 After selecting DIAG press the MODE button 7 Select the diagnostic code number corresponding to the fault code number by pressing the UP and DOWN buttons NOTE The diagnostic code number appears on the LCD 01 70 To decrease the selected diagnostic code number press the DOWN button Press the DOWN but ton for 1 second or longer to automatically decrease the diagnostic code number...

Page 308: ...function in ECU 01 19 A break or disconnection of the blue yellow lead of the ECU is detected Open or short circuit in wire harness ECU coupler Malfunction in ECU 20 21 Coolant temperature sen sor open or short circuit detected Open or short circuit in wire harness Defective coolant temperature sensor Malfunction in ECU Improperly installed coolant temperature sensor 06 22 Intake air temperature s...

Page 309: ...e internal memory Fault code No Symptom Probable cause of malfunction Diagnostic code No Diag nostic code No Item FI diagnostic tool display Checking method 01 Throttle angle Check for changes in dis played values while open ing and closing the throttle Fully closed position 14 20 Fully open position 97 107 03 Intake air pressure Displays the intake air pres sure Set the engine stop switch to then...

Page 310: ...ault code dis play No history 00 History exists 01 CO adjustment value is detected 61 Malfunction history code display No history 00 History exists Fault codes 12 50 If more than one code number is detected the dis play alternates every two seconds to show all the de tected code numbers When all code numbers are shown the display repeats the same process 62 Malfunction history code erasure No hist...

Page 311: ...adlight relay Actuates the headlight relay for five cycles of five sec onds ON 2 seconds OFF 3 seconds Illuminates the WARNING LED on the FI diagnostic tool the engine trouble warn ing light and headlight Check the operating sound of the headlight relay five times 54 FID fast idle solenoid When the MODE button is pressed the FID fast idle so lenoid is actuated five times at one second intervals Il...

Page 312: ... operation table Fault code No 12 Symptom No normal signals are received from the crankshaft posi tion sensor Diagnostic code No Order Item components and probable cause Check or maintenance job Reinstatement method 1 Installed condition of crankshaft posi tion sensor Check for looseness or pinching Cranking the engine 2 Connections Crankshaft position sensor coupler Main wire harness ECU coupler ...

Page 313: ...the coupler If there is a malfunction repair it and connect the coupler se curely Setting the main switch to ON 2 Open or short circuit in wire harness Repair or replace if there is an open or short circuit Between throttle body sensor assembly coupler and ECU coupler gray red gray red pink white pink white gray black gray black 3 Defective intake air pressure sensor Execute the diagnostic mode Co...

Page 314: ...s ECU coupler Check the coupler for any pins that may have pulled out Check the locking condition of the coupler If there is a malfunction repair it and connect the coupler se curely Starting the en gine and oper ating it at idle 2 Defective intake air pressure sensor Execute the diagnostic mode Code No 03 Replace the throttle body if de fective Refer to CHECKING THE THROTTLE BODY SENSOR ASSEMBLY ...

Page 315: ...it in wire harness Repair or replace if there is an open or short circuit Between throttle body sensor assembly coupler and ECU coupler gray red gray red gray black gray black yellow yellow 3 Throttle position sensor lead wire open circuit output voltage check Check for open circuit and re place the throttle body gray red gray black Open circuit item Output voltage Ground wire open circuit 5 V Out...

Page 316: ...ault code No 19 Symptom A break or disconnection of the blue yellow lead of the ECU is detected Diagnostic code No 20 Sidestand switch Order Item components and probable cause Check or maintenance job Reinstatement method 1 Connections Wire harness ECU coupler Execute the diagnostic mode Code No 20 Check the coupler for any pins that may have pulled out Check the locking condition of the coupler I...

Page 317: ...or Coolant temperature sensor coupler Main wire harness ECU coupler Check the coupler for any pins that may have pulled out Check the locking condition of the coupler If there is a malfunction repair it and connect it securely 3 Open or short circuit in wire harness Repair or replace if there is an open or short circuit Between coolant temperature sensor coupler and ECU cou pler gray black gray bl...

Page 318: ...ition of the couplers If there is a malfunction repair it and connect the coupler se curely Setting the main switch to ON 2 Open or short circuit in wire harness Repair or replace if there is an open or short circuit Between throttle body sensor assembly coupler and ECU coupler brown white brown white gray black gray black 3 Defective intake air temperature sen sor Execute the diagnostic mode Code...

Page 319: ...ctive Refer to CHECKING THE LEAN ANGLE SENSOR on page 8 69 Fault code No 33 Symptom Primary lead of the ignition coil open circuit detected Diagnostic code No 30 Ignition coil Order Item components and probable cause Check or maintenance job Reinstatement method 1 Connections Ignition coil connector primary coil side Main wire harness ECU coupler Check the connector and cou pler for any pins that ...

Page 320: ... Code No 36 Replace if defective Refer to CHECKING THE FUEL INJECTOR on page 7 6 Fault code No 41 Symptom Lean angle sensor open or short circuit detected Diagnostic code No 08 Lean angle sensor Order Item components and probable cause Check or maintenance job Reinstatement method 1 Connections Lean angle sensor coupler Main wire harness ECU coupler Check the coupler for any pins that may have pul...

Page 321: ...r sub wire harness Repair or replace if there is an open or short circuit Between speed sensor coupler and ECU coupler gray gray gray black gray black gray red gray red 3 Defective speed sensor Execute the diagnostic mode Code No 07 Replace if defective Refer to CHECKING THE SPEED SENSOR on page 8 72 Fault code No 44 Symptom Error is detected while reading from or writing on EE PROM Diagnostic cod...

Page 322: ...function in rectifier regulator Replace if defective Refer to CHARGING SYS TEM on page 8 11 4 Open or short circuit in wire harness Repair or replace if there is an open or short circuit Between battery and main switch coupler red red Between main switch coupler and fuse box coupler brown blue brown blue Between fuse box coupler and ECU coupler red black red black Fault code No 50 Symptom Faulty E...

Page 323: ...FUEL INJECTION SYSTEM 8 52 YamahaR125 COM ...

Page 324: ...RE HARNESS B W Dg BLACK Ch Y L G W Sb Ch Dg BLACK B W Sb G W Y L B WIRE HARNESS SUB WIRE HARNESS SUB WIRE HARNESS R B Y R G R Gy B OFF ON PASS R Gy B W W W W R W O Br Br L R Y Dg Dg Br L R B Br L R W R Gy R Gy R R R B P W P W Gy B Gy B Br W Br W Y Y G R O B Y R O O B R W G R Gy B Gy B Gy R Y G Y G Y W G W B W Gy Gy R L Y Br L L B B R B B Br Br W Br W Br B B R B L W R W Sb W P B Ch Dg G Y R YR Y L ...

Page 325: ...FUEL PUMP SYSTEM 8 54 4 Main fuse 5 Main switch 9 Battery 17 Engine stop switch 25 ECU engine control unit 30 Fuel pump 64 Ignition fuse YamahaR125 COM ...

Page 326: ...y fluid Clean the battery terminals Recharge or replace the battery 3 Check the main switch Refer to CHECKING THE SWITCHES on page 8 59 Replace the main switch 4 Check the engine stop switch Refer to CHECKING THE SWITCHES on page 8 59 The engine stop switch is faulty Replace the right handlebar switch 5 Check the fuel pump operation Refer to CHECKING THE FUEL PRESSURE on page 7 2 Replace the fuel ...

Page 327: ...FUEL PUMP SYSTEM 8 56 YamahaR125 COM ...

Page 328: ...ELECTRICAL COMPONENTS 8 57 EAS27971 ELECTRICAL COMPONENTS 1 4 8 18 24 2 3 5 6 7 9 10 11 12 13 14 15 16 17 19 20 21 22 23 YamahaR125 COM ...

Page 329: ... 6 FID fast idle solenoid 7 Rectifier regulator 8 Lean angle sensor 9 Starting circuit cut off relay 10 Turn signal relay 11 Radiator fan motor relay 12 Headlight relay 13 ECU engine control unit 14 Fuse box 15 Starter relay 16 Battery 17 Rear brake light switch 18 Sidestand switch 19 Neutral switch 20 Crankshaft position sensor 21 Coolant temperature sensor 22 Speed sensor 23 Radiator fan 24 Horn...

Page 330: ...7980 CHECKING THE SWITCHES OFF ON R R L B L B Br L Sb W Br L L Y L Y Dg Ch Br W P B G Y L B Y R Y R B L B BLACK RED B R G Y B B Y B G Dg Ch Br W R Y P L B R W R W R W R W L W B B B BLUE PASS 1 2 3 4 5 6 7 8 9 10 11 12 YamahaR125 COM ...

Page 331: ...utch switch 2 Main switch 3 Front brake light switch 4 Sidestand switch 5 Rear brake light switch 6 Neutral switch 7 Turn signal switch 8 Horn switch 9 Dimmer switch 10 Pass switch 11 Engine stop switch 12 Start switch YamahaR125 COM ...

Page 332: ... the Ω 1 range When checking for continuity switch back and forth between the switch positions a few times The switches and their terminal connections are illustrated as in the following example of the main switch The switch positions a are shown in the far left column and the switch lead colors b are shown in the top row The continuity i e a closed circuit between switch terminals at a given swit...

Page 333: ...e bulbs The following procedure applies to all of the bulbs 1 Remove Bulb WARNING EWA5D71001 Since the headlight bulbs get extremely hot keep flammable products and your hands away from them until they have cooled down CAUTION ECA5D71001 Be sure to hold the socket firmly when re moving the bulb Never pull the lead other wise it may be pulled out of the terminal in the coupler Avoid touching the gl...

Page 334: ... the pocket tester to the fuse and check the continuity NOTE Set the pocket tester selector to Ω 1 b If the pocket tester indicates replace the fuse 3 Replace Blown fuse a Set the main switch to OFF b Install a new fuse of the correct amperage rating c Set on the switches to verify if the electrical circuit is operational d If the fuse immediately blows again check the electrical circuit WARNING E...

Page 335: ...IS on page 4 1 2 Disconnect Battery leads from the battery terminals CAUTION ECA5D71041 First disconnect the negative battery lead 1 then the positive battery lead 2 3 Remove Battery 4 Check Electrolyte level The electrolyte level should be between the minimum level mark a and the maximum level mark b Below the minimum level mark Add dis tilled water to the proper level CAUTION ECA13610 Add only d...

Page 336: ...ttery cells occurs as indicated by the battery plates turning white or material accumulating in the bottom of the battery cell specific gravity readings after a long slow charge indicate that one battery cell s charge is lower than the rest warpage or buckling of the battery plates or in sulators is evident 7 Check Battery breather hose and battery vent Obstruction Clean Damage Replace 8 Install B...

Page 337: ...to the turn signal relay cou pler is faulty and must be repaired Pocket tester 90890 03112 Analog pocket tester YU 03112 C 1 Positive battery terminal 2 Negative battery terminal 3 Positive tester probe 4 Negative tester probe Result Continuity between 3 and 4 1 Positive battery terminal 2 Negative battery terminal 3 Positive tester probe 4 Negative tester probe R R W L B R B 1 2 4 3 1 3 2 4 R B L...

Page 338: ...table Turn signal relay input voltage DC 12 V Pocket tester 90890 03112 Analog pocket tester YU 03112 C Positive tester probe brown 1 Negative tester probe ground Turn signal relay output voltage DC 12 V Pocket tester 90890 03112 Analog pocket tester YU 03112 C Positive tester probe brown white 1 Negative tester probe ground Br W Br 1 Pocket tester 90890 03112 Analog pocket tester YU 03112 C Conti...

Page 339: ...connectors from the ignition coil terminals b Connect the pocket tester Ω 1 to the igni tion coil as shown c Measure the primary coil resistance 2 Check Secondary coil resistance Out of specification Replace a Disconnect the spark plug cap from the igni tion coil b Connect the pocket tester Ω 1k to the ig nition coil as shown Resistance 5 0 kΩ Pocket tester 90890 03112 Analog pocket tester YU 0311...

Page 340: ... occurs EAS28120 CHECKING THE CRANKSHAFT POSITION SENSOR 1 Disconnect Crankshaft position sensor coupler from the wire harness 2 Check Crankshaft position sensor resistance Out of specification Replace the crank shaft position sensor stator assembly a Connect the pocket tester Ω 100 to the crankshaft position sensor coupler as shown b Measure the crankshaft position sensor re sistance EAS28130 CHE...

Page 341: ...is check is likely to produce sparks therefore make sure no flammable gas or fluid is in the vicinity b Check the starter motor operation EAS28150 CHECKING THE STATOR COIL 1 Disconnect Stator coil coupler from the wire harness 2 Check Stator coil resistance Out of specification Replace the crank shaft position sensor stator assembly a Connect the pocket tester Ω 1 to the stator coil coupler as sho...

Page 342: ... Disconnect the horn connectors from the horn terminals b Connect the pocket tester Ω 1 to the horn terminals c Measure the horn resistance 2 Check Horn sound Faulty sound Adjust or replace a Connect a battery 12 V to the horn b Turn the adjusting screw in direction a or b until the specified horn sound is obtained Rectifier regulator output voltage 14 V at 5000 r min Pocket tester 90890 03112 Ana...

Page 343: ...wheel the voltage reading should cycle from 0 V to 5 0 V to 0 V to 5 0 V EAS28250 CHECKING THE RADIATOR FAN MOTOR 1 Check Radiator fan motor Faulty rough movement Replace a Disconnect the radiator fan motor coupler from the wire harness b Connect the battery DC 12 V as shown Sender unit resistance full 0 0 7 0 Ω Sender unit resistance empty 90 0 103 0 Ω Pocket tester 90890 03112 Analog pocket test...

Page 344: ...temperature e Check the coolant temperature sensor resis tance 3 Install Coolant temperature sensor EAS5D71029 CHECKING THE THROTTLE BODY SENSOR ASSEMBLY WARNING EWA5D71011 Do not remove the throttle body sensor as sembly Handle the throttle body sensor assembly with special care Never subject the throttle body sensor as sembly to strong shocks If the throttle body sensor assembly is dropped repla...

Page 345: ...Set the main switch to ON c Measure the intake air pressure sensor out put voltage Intake air temperature sensor 1 Check Intake air temperature sensor resistance Out of specification Replace the throttle body a Connect the pocket tester Ω 1k to the throttle body sensor assembly coupler as shown Throttle position sensor input voltage 5 V Positive tester probe yellow terminal 3 Negative tester probe...

Page 346: ... solenoid cou pler from the FID b Connect the pocket tester Ω 10 to the ter minals of the FID fast idle solenoid c Measure the FID fast idle solenoid resis tance Out of specification Replace the throttle body assembly Positive tester probe red black terminal 1 Negative tester probe yellow red terminal 2 Pocket tester 90890 03112 Analog pocket tester YU 03112 C FID fast idle solenoid resistance 31 ...

Page 347: ...PEED 9 1 POOR MEDIUM AND HIGH SPEED PERFORMANCE 9 2 FAULTY GEAR SHIFTING 9 2 SHIFT PEDAL DOES NOT MOVE 9 2 JUMPS OUT OF GEAR 9 2 FAULTY CLUTCH 9 2 OVERHEATING 9 2 OVERCOOLING 9 3 POOR BRAKING PERFORMANCE 9 3 FAULTY FRONT FORK LEGS 9 3 UNSTABLE HANDLING 9 3 FAULTY LIGHTING OR SIGNALING SYSTEM 9 4 YamahaR125 COM ...

Page 348: ... pump 3 Throttle body Deteriorated or contaminated fuel Sucked in air Electrical system 1 Battery Discharged battery Faulty battery 2 Fuse s Blown damaged or incorrect fuse Improperly installed fuse 3 Spark plug Incorrect spark plug gap Incorrect spark plug heat range Fouled spark plug Worn or damaged electrode Worn or damaged insulator Faulty spark plug cap 4 Ignition coil Cracked or broken ignit...

Page 349: ...nd shift forks Foreign object in a shift drum groove Seized shift fork Bent shift fork guide bar Transmission Seized transmission gear Foreign object between transmission gears Improperly assembled transmission EAS28550 JUMPS OUT OF GEAR Shift shaft Incorrect shift pedal position Improperly returned stopper lever Shift forks Worn shift fork Shift drum Incorrect axial play Worn shift drum groove Tr...

Page 350: ...ase on the brake pad Incorrect brake fluid level EAS28660 FAULTY FRONT FORK LEGS Leaking oil Bent damaged or rusty inner tube Cracked or damaged outer tube Improperly installed oil seal Damaged oil seal lip Incorrect oil level high Loose damper rod assembly bolt Damaged damper rod assembly bolt copper washer Cracked or damaged front fork cap O ring Malfunction Bent or damaged inner tube Bent or da...

Page 351: ...aulty light switch Headlight bulb life expired Tail brake light does not come on Too many electrical accessories Incorrect connection Burnt out tail brake light LED Turn signal does not come on Faulty turn signal switch Faulty turn signal relay Burnt out turn signal bulb Incorrect connection Damaged or faulty wire harness Improperly grounded circuit Faulty battery Blown damaged or incorrect fuse T...

Page 352: ...t 42 Turn signal relay 43 Horn 44 Headlight relay 45 Left handlebar switch 46 Pass switch 47 Dimmer switch 48 Horn switch 49 Turn signal switch 50 Right headlight assembly 51 Headlight low beam 52 Auxiliary light 53 Left Headlight assembly 54 Headlight high beam 55 Meter assembly 56 Multi function meter 57 Tachometer 58 Meter light 59 Coolant temperature warning light 60 High beam indicator light ...

Page 353: ...YamahaR125 COM ...

Page 354: ...YamahaR125 COM ...

Page 355: ... HARNESS C WIRE HARNESS SUB WIRE HARNESS B W Dg BLACK Ch Y L G W Sb Ch Dg BLACK B W Sb G W Y L B WIRE HARNESS SUB WIRE HARNESS SUB WIRE HARNESS R B Y R G R Gy B OFF ON PASS R Gy B W W W W R W O Br Br L R Y Dg Dg Br L R B Br L R W R Gy R Gy R R R B P W P W Gy B Gy B Br W Br W Y Y G R O B Y R O O B R W G R Gy B Gy B Gy R Y G Y G Y W G W B W Gy Gy R L Y Br L L B B R B B Br Br W Br W Br B B R B L W R ...

Page 356: ...CK BLACK RED RED Y BLACK A WIRE HARNESS C WIRE HARNESS SUB WIRE HARNESS BLACK BLACK B WIRE HARNESS SUB WIRE HARNESS SUB WIRE HARNESS OFF ON PASS A A A A B A A B B B B B C C 13 1 2 3 4 5 8 7 9 10 11 30 31 22 21 20 19 18 23 26 27 28 29 25 32 12 24 33 36 37 38 39 40 41 45 46 47 48 49 34 35 42 43 44 52 51 50 52 54 53 66 65 64 55 57 56 58 59 61 62 60 63 67 14 6 15 16 17 YamahaR125 COM ...