Robin America EX30, Service Manual

Page 1: ...SERVICE MANUAL EX30 ENGINES Model PUB ES2268 Rev 10 06 ...

Page 2: ... Copyright 2006 Robin America Inc 940 Lively Blvd Wood Dale IL 60191 Phone 630 350 8200 Fax 630 350 8212 e mail sales robinamerica com www robinamerica com ...

Page 3: ... TOOLS 11 5 3 DISASSEMBLY PROCEDURE 12 5 4 REASSEMBLY PROCEDURE 26 6 ENGINE OIL 42 7 MAGNETO 43 8 WIRING DIAGRAM 45 9 ELECTRIC STARTER 47 10 OIL SENSOR 49 11 AUTOMATIC DECOMPRESSION SYSTEM 50 12 CARBURETOR 51 13 RECOIL STARTER 55 14 INSTALLATION 59 15 TROUBLESHOOTING 61 16 STANDARD REPAIR TABLES 67 16 1 STANDARD DIMENSIONS AND LIMITS OF USE 67 16 2 TIGHTENING TORQUE 73 17 MAINTENANCE AND STORAGE 7...

Page 4: ...ive detergent oil API SE or higher grade SAE 10W 30 etc Oil Capacity Liter 1 0 Fuel Automotive Gasoline Unleaded Spark Plug NGK BR 6HS Starting System Recoil starter Electric starter Dry Weight kg 21 Dimensions L x W x H mm 415 x 424 x 319 Valve Clearance Intake and Exhaust 0 12 mm 0 0047 in Note Adjust the valve clearance while the engine is cold Emissions Durability Period California only 500 ho...

Page 5: ...l combustion engine standard test code J1349 2 2 CONTINUOUS RATED OUTPUT The continuous rated output is the output of an engine at optimum governed speed which is most favorable from the view point of engin s life and fuel consumption When the engine is installed on a certain equipment it is recommended that the continuous output required from the equipment to be kept below this continuous rated o...

Page 6: ... 0 0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5 5 0 5 5 6 0 6 5 7 0 kW 17 0 18 0 19 0 20 0 HP r p m REVOLUTION TORQUE OUTPUT 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 10 0 1 7 1 8 1 9 2 0 RECOMMENDED HORSEPOWER RANGE MAXIMUM HORSEPOWER MAXIMUM TORQUE CONTINUOUS RATED HP ...

Page 7: ...h lower moment of deformation significantly increases reliability and engine life Superior Cooling and Lubrication System Heat reduction is achieved by more efficient larger and more numerous cooling fins on crankcase cylinder and mounting base as well as by outstanding oil delivery system Large Ball Bearings on both ends of crankshaft for maximum stability under demanding loads Cast Iron Cylinder...

Page 8: ...d bosses are machined into the cover to facilitate the direct coupling of the engine with machines such as generators and pumps There is an oil filling port with oil gauge on either side of the cover 4 3 CRANKSHAFT The crankshaft is made of spheroidal graphite cast iron and the crank pin is high frequency induction hardened The crank sprocket used to drive the chain and the gear used to drive the ...

Page 9: ...sprocket are made of special sintered alloy They are constructed as a single piece The camshaft is provided with intake and exhaust cam and the decompression release lever is mounted on the sprocket shaft end side 4 7 VALVE ARRANGEMENT This engine has a chain driven overhead cam and overhead valve construction with a single cam performing both intake and exhaust operations 4 8 CYLINDER HEAD The cy...

Page 10: ...2 TIMING CHAIN Timing chain system is adopted and designed for lubricating for the upper portion of cylinder head The timing chain is engaged between the sprocket portion of integrated camshaft in the cylinder head and the crankshaft gear sprocket The sprocket teeth in particular shape are adopted to enhance the durability and to realize low noise level 4 13 IGNITION SYSTEM The ignition system is ...

Page 11: ...r cleaner that is quieter than conventional ones A semi wet urethane foam element is used in the urethane foam air cleaner 4 16 DECOMPRESSION SYSTEM The automatic decompression system is mounted on the camshaft It opens the exhaust valve before the compression top thereby alleviating the compression pressure and reducing the force required to pull the recoil starter During engine operation the dec...

Page 12: ...L VIEW OF THE ENGINE Cross sectional view across the shaft DUCT BLOWER HOUSING STARTING PULLEY RECOIL STARTER FLYWHEEL OIL SENSOR MAIN BEARING COVER CONNECTING ROD CRANKSHAFT GOVERNOR GEAR GOVERNOR LEVER GOVERNOR SHAFT ...

Page 13: ...shaft EXHAUST PIPE CONNECTING ROD CRANKSHAFT CRANKCASE OIL DRAIN PLUG TIMING CHAIN GOVERNOR GEAR GOVERNOR LEVER PISTON DUCT CHAIN GUIDE EXHAUST VALVE OIL SENSOR OIL GAUGE PISTON PIN PISTON RING TENSIONER ROCKER ARM INTAKE VALVE CAMSHAFT ...

Page 14: ...his will make reassembly easier 3 To prevent parts from being mislaid keep each group provisionally assembled after removing the parts from the engine 4 Handle the disassembled parts with the utmost care Clean them with cleaning oil if necessary 5 Use the correct tools in the correct way when disassembling and reassembling the engine 5 2 SPECIAL TOOLS 5 DISASSEMBLY AND REASSEMBLY Tool name Use Com...

Page 15: ...located on both sides of the case Take care not to lose the gaskets 2 To discharge oil quickly remove the oil guage 14 mm spanner 2 Drain the fuel 1 Drain fuel from the carburetor drain See Figure STEP2 A 2 Disconnect the fuel pipe from the carburetor See Figure STEP2 B OIL GAUGE GASKET GASKET DRAIN PLUG STEP 1 STEP 2 STEP 2 STEP2 A STEP2 B ...

Page 16: ... spanner 4 Air cleaner Remove the element and remove the air cleaner while pulling the breather pipe away from the rocker cover 10 mm box spanner M6 nut 2 pcs M6 x 20 1 pc M6 x 20 FLANGE BOLT 1 pc M6 FLANGE NUT 2 pcs AIR CLEANER BREATHER PIPE GASKET CLAMP CLEANER BODY COMP COVER COMP ELEMENT STEP 3 STEP 4 BRACKET ...

Page 17: ...6 x 14mm 4 pcs 7 Blower housing Baffle 1 case Baffle 2 head 1 Remove the blower housing from the crankcase 2 Remove the baffle 1 case and baffle 2 head 10 mm box spanner M6 x 14mm 4 pcs 10 mm box spanner or spanner M6 x 12mm 1 pc Baffle 2 head STEP 5 STEP 6 STEP 7 PURSE LOCK M6 x 14 BOLT 4 pcs BAFFLE 2 HEAD RECOIL STARTER BLOWER HOUSING M6 x 12 BOLT 1 pc SPONGE 4 M4 x 12 TAPPING SCREW 2 pcs M6 x 1...

Page 18: ...m the cylinder head Take care not to lose the gasket Take care not to cut your hand with the muffler gasket Seal the exhaust port with adhesive tape or plug it with cloth to prevent nuts and other objects from falling inside 12mm box spanner M8 nut 4 pcs STEP 9 STEP 8 M8 NUT 2 pcs GASKET MUFFLER It has two faces M6 x 12 BOLT 3 pcs DUCT CASE EXHAUST PIPE A A GASKET EXHAUST M8 NUT 2 pcs ...

Page 19: ...spring from the carburetor 14 mm spanner 11 Carburetor Insulator 1 Remove the carburetor from the cylinder head 2 Remove the insulator 12 Speed control lever and Bracket Remove the speed control lever and bracket from the cylinder head 10 mm box spanner M6 x 12mm 2 pcs STEP 10 STEP 11 STEP 12 GOVERNOR LEVER GOVERNOR ROD and ROD SPRING GOVERNOR SPRING SPEED CONTROL LEVER and BRACKET INSULATOR GASKE...

Page 20: ...ver or other object between the flywheel blades otherwise the risk of damaging the blades might be occured 2 Knock the wrench with a hammer in a counter clockwise direction 24 mm box spanner or socket wrench M18 nut 15 Flywheel Remove the flywheel from the crankshaft Leave the nut temporarily to prevent the flywheel from dropping out Fit the flywheel puller as shown in Figure STEP15 A and remove t...

Page 21: ... grounding cable from battery 2 Disconnect the wire leading from the key switch ST terminal to the magnetic switch 3 Disconnect the wire that connects the positive terminal of the battery to the magnetic switch 4 Remove the electric starter 12 mm box spanner M8 nuts 12 mm box spanner ELECTRIC STARTER option STEP 16 M8 x 28 BOLT 2 pcs M8 NUT 1 pc ...

Page 22: ...e charge coil Remove the wire clamp together box spanner M6 x 20mm 2 pcs screwdriver 19 Spark plug Remove the spark plug from the cylinder head 21 mm plug wrench SPARK PLUG CLAMP VIEW A A BAFFLE 1 CASE CHARGE COIL OPTION CHARGE COIL M8 x 12 FLANGE BOLT 1 pc For the model without electric starter STEP 17 STEP 18 STEP 19 M6 x 20 SCREW WASHER 2 pcs ...

Page 23: ...e the pin rocker arm and the rocker arm from the cylinder head at the compression top dead center See Figure STEP21 A ROCKER ARM EXHAUST VALVE SIDE PIN ROCKER ARM CLOSE UP A A ROCKER ARM INTAKE VALVE SIDE ROCKER COVER GASKET ROCKER COVER M6 x 12 BOLT 4 pcs STEP 21 STEP 20 ROCKER ARM EXHAUST VALVE SIDE ROCKER ARM INTAKE VALVE SIDE PIN ROCKER ARM Punch marks The position of compression top dead cent...

Page 24: ...er from the crankcase Remove the main bearing cover while tapping gently around the cover using a plastic hammer or similar tool See Figure STEP22 A Be careful not to damage the oil gauge or oil seal or not to lose the pipe knocks 12 mm box spanner M8 35mm 7 pcs MAIN BEARING COVER M8 x 35mm 7 pcs PIPE KNOCK STEP 22 STEP22 A ...

Page 25: ...h the O ring 4 Remove the chain from the camshaft sprocket and then take out the camshaft See Figure STEP23 C 5 Remove the chain from the crankshaft M10 box spanner or spanner M6 12mm 1 pc PIN CAMSHAFT STEP 23 TENSIONER SPRING TENSIONER CHAIN PIN TENSIONER M6 x 12 BOLT 1 pc Bolt used to prevent the pin camshaft from coming out CAMSHAFT CHAIN STEP 23 PIN TENSIONER CAMSHAFT CHAIN M6 x 12 BOLT 1 pc B...

Page 26: ...the inner side of the crankcase it might be damaged 12 mm box spanner M8 68mm 4 pcs M8 33mm 1 pc 25 Intake and exhaust valves 1 Remove the collet valve from the spring retainer See Figure STEP25 A 2 Remove the intake valve and the exhaust valve M8 x 33 BOLT 1 pc This bolt is same as the main bearing cover bolt STEP 24 STEP 25 PIPE KNOCK GASKET CYLINDER HEAD M8 x 68 BOLT 4 pcs EXHAUST VALVE INTAKE ...

Page 27: ...iston from the upper part of the cylinder 10 mm box spanner M7 40mm 2 pcs 27 Piston and piston rings 1 Remove the piston clips 2 pcs Take out the piston pin and then remove the piston from the connecting rod small end taking care not to damage the connecting rod small end 2 Remove the piston rings from the piston by spreading them at the gap Take special care not to damage the rings when doing thi...

Page 28: ...lastic hammer taking care not to damage the oil seal See Figure STEP28 A Plastic hammer 29 Oil sensor option 1 Remove the clamp See Figure Step29 A 2 Remove the oil sensor from the crankcase M6 12mm 1 pc M6 16mm 2 pcs CRANKCASE WOODRUFF KEY CRANKSHAFT M6 x 16 BOLT 2 pcs OIL SENSOR STEP 28 STEP 29 SHIELD PLATE For charge coil only M6 x 10 TAPPING BOLT 1 pc WIRE CLAMP OIL SENSOR WIRE CLAMP STEP28 A ...

Page 29: ...pply oil to all moving parts 8 Check clearances and end plays and adjust if necessary 9 When mounting any major part during reassembly of the engine rotate it with your hand to check for any jamming or abnormal noise 5 4 2 ASSEMBLY STEPS AND PRECAUTIONS 1 OIL SENSOR a Mount the oil sensor and fix the wire with the clamp b Mount the shield plate only for charge coil type OIL SENSOR SHIELD PLATE OS ...

Page 30: ... 2 BARREL THREE PIECE CONSTRUCTION 1 2 MARK N 4 PISTON AND CONNECTING ROD The piston is attached to the connecting rod by the piston pin When assembling the piston and connecting rod make sure to align the mark on the piston head with the MAG mark on the connecting rod NOTE1 Before assembling the connecting rod apply oil to its small end NOTE2 Be sure to insert the clips in the two ends of the pis...

Page 31: ...he connecting rod into the cylinder NOTE2 The piston ring gaps should be positioned around the piston at 90 degree intervals b Rotate the crankshaft down to the bottom dead center and lightly tap the piston head until the large end of the connecting rod touches the crank pin c To mount the connecting rod line up the matching marks and fit the clinch portions firmly together d Check for free moveme...

Page 32: ...ew one if it shows signs of wear Refer to the STANDARD REPAIR TABLES on page 71 and 72 NOTE2 Carefully scrape off any carbon deposits on the combustion chamber Apply oil to the valve stems before mounting the intake and exhaust valves Insert the valves in the cylinder head and place it on a level workbench Next mount the valve springs the spring retainers and collet valves Mount the stem seal on t...

Page 33: ...ry and then tighten longer ones M8 68mm flange bolt 4pcs by 26 1 N m 2 When replace to new cylinder head and flange bolts Oil the screw thread Tighten all bolts 5pcs by 18 1 N m primary and then tighten longer ones M8 68mm flange bolt 4pcs by 29 1 N m 9 SETTING THE TIMING CHAIN a Align the timing mark on the crankshaft sprocket with the mark plate of the timing chain b Align the timing mark on the...

Page 34: ... the pin camshaft from coming out CAMSHAFT CHAIN M6 x 12 BOLT 1 pc Bolt used to prevent the pin camshaft from coming out PIN CAMSHAFT TENSIONER PIN TENSIONER SPRING TENSIONER PIN TENSIONER 11 MOUNTING THE TENSIONER PIN CAMSHAFT TENSIONER SPRING TENSIONER CHAIN PIN TENSIONER M6 x 12 BOLT 1 pc Bolt used to prevent the pin camshaft from coming out CAMSHAFT CHAIN ...

Page 35: ...ace of the crankcase To avoid damaging the oil seal lip wrap the crankshaft key way portion with polyvinyl tape before mounting the main bearing cover NOTE Be careful that the lever portion of governor shaft does not face the main bearing cover Tightening torque 17 0 18 0 N m 170 180 kgf cm 12 3 13 0 ft lb MAIN BEARING COVER M8 x 35 BOLT 7 pcs PIPE KNOCK ...

Page 36: ...CE ADJUSTMENT Temporarily fit the flywheel Rotate the crankshaft up to the compression top dead center and insert the thickness gauge between the valve and the adjusting screw of rocker arm to measure the clearance Adjustment method Loosen the nut on the adjustment screw and turn the screw to adjust the valve clearance When the valve clearance is correct tighten the nut Valve clearance when the en...

Page 37: ...cessary Spark plug NGK BR 6HS Electrode gap 0 6 mm 0 7 mm Tightening torque New spark plug Re tightening torque 12 0 15 0 N m 120 150 kgf cm 8 7 10 8 ft lb 23 0 27 0 N m 230 270 kgf cm 16 6 19 5 ft lb 17 BAFFLE 1 CASE Align the top and bottom of the baffle 1 case with the crankcase and mount it with the bolts Model without electric starter M8 12 mm bolt 1 pc Model with electric starter Mount the e...

Page 38: ...together with the starting pulley Tightening torque 59 0 64 0 N m 590 640 kgf cm 42 7 46 3 ft lb M8 nut 1 pc FLYWHEEL STARTING PULLEY Align the 2 bosses of starting pulley with the depression of flywheel 19 IGNITION COIL When mounting the ignition coil insert a thickness gauge between the ignition coil and the flywheel to check the air gap Air gap 0 3 mm 0 5 mm Tightening torque 7 0 9 0 N m 70 90 ...

Page 39: ...Replace the gasket of insulator with a new one and mount the insulator on the cylinder head intake side b Align the cord of ignition coil with the cut out in the insulator to fit the carburetor BAFFLE 2 HEAD M6 x 12 BOLT 1 pc SPEED CONTROL LEVER and BRACKET INSULATOR GASKET GASKET M6 x 12 BOLT 2 pcs CARBURETOR BAFFLE 2 HEAD a b c a b c ...

Page 40: ...r lever then mount the governor lever on the governor shaft Do not adjust the bolt on the governor lever yet c Connect the governor lever and the speed control lever with the governor spring NOTE See page 38 for details on the adjustment method after mounting air cleaner base GOVERNOR LEVER GOVERNOR ROD and ROD SPRING GOVERNOR SPRING Short length side Long length side A VIEW A ...

Page 41: ... 22 0 N m 180 220 kgf cm 13 0 15 9 ft lb M8 NUT 2 pcs M6 x 12 BOLT 3 pcs DUCT CASE EXHAUST PIPE M8 NUT 2 pcs GASKET MUFFLER It has two faces A A GASKET EXHAUST 24 BLOWER HOUSING AND RECOIL STARTER a Align the cord of ignition coil with the cut out with that of the blower housing to mount the blower housing on the crankcase M6 14 mm bolt 4 pcs b Mount the recoil starter on the blower housing M6 14 ...

Page 42: ...governor gear Since it automatically adjusts the throttle valve of the carburetor by means of a link mechanism it is possible to maintain a constant engine speed even with load variations 1 Turn the speed control lever to the full speed position making sure that the carburetor throttle valve is fully open 2 Hold the top of the governor shaft with the plier and turning it clockwise as far as it wil...

Page 43: ... CP5 a Mount the stop switch on the blower housing b Refer to the wiring diagram See page 45 and 46 for wiring details STOP SWITCH 27 AIR CLEANER Mount the air cleaner element and cleaner cover CLEANER BODY COMP COVER COMP ELEMENT ...

Page 44: ...ompletely overhauled by being fitted with a new piston rings valves and connecting rod should be thoroughly RUN IN before being put back into service Good bearing surfaces and running clearances between the various parts can only be established by operating the engine under reduced speed and loads for a short period of time While the engine is being tested check for oil leaks Make final carburetor...

Page 45: ...ltigrade 5W 10W 20W 20 30 40 10W 30 10W 40 Be sure to use automobile engine oil of the viscosity shown in the table above depending on environmental air temperature When the air temperature falls below 20 C or rises above 40 C be sure to choose engine oil of appropriate viscosity and grade according to the prevailing conditions Care must be taken when using multi grade engine oil because the oil c...

Page 46: ...s according to the following procedure 1 Carefully check the high tension cable for any damage or short circuiting 2 Check the sparking Take the spark plug out of the cylinder head connect the spark plug with the plug cap and ground it on the cylinder head or any other metallic part of the engine The gap between the electrodes of the spark plug should be between 0 6 mm and 0 7 mm Rotate the engine...

Page 47: ...ne revolution is less advanced as shown in the above chart c At higher engine revolution over 2 000rpm advancing control circuit operates to run the gate current I4 to turn the control thyristor ON thus the current I1 bypass the thyristor as current I5 At this moment the power transistor turns OFF and the current I2 is shut off abruptly resulting in the high voltage generated in the secondary coil...

Page 48: ... WITH ELECTRIC STARTER Stop switch Flywheel Ignition coil with built in transistor Black Spark plug M M ST B LA108 LA408 Black Red Diode rectifier Ignition coil Spark plug Key switch Battery 12V24AH Electric starter Magneto Key switch M M B S OFF ON START Charge coil ...

Page 49: ... 46 8 3 MODEL WITH OIL SENSOR To LED Lamp Yellow Yellow Red Black Oil sensor control unit Orange Orange Body earth Black White Black To stop switch Spark plug Oil sensor ...

Page 50: ...gnet incorporated into the float and the oil sensor In accordance with the oil level the float moves up and down When the oil level is upper level the float moves up When the oil level is lower level the float moves down The permanent magnet is close to the lead switch and the lead switch is activated by the magnetic force NOTE With regards to the wiring diagram please refer to the section 8 3 pag...

Page 51: ... the crescent cam projects above the cam profile and lifts up the rocker arm exhaust because the force of the return spring on the weight is larger than the centrifugal force on the weight 11 AUTOMATIC DECOMPRESSION SYSTEM When the cranking speed reaches a specified r p m the crescent cam is retracted under the cam profile because the centrifugal force applied to the flyweight becomes larger than ...

Page 52: ...air jet and then the fuel air mixture is fed to the engine through the pilot outlet and the bypass During idling fuel is fed to the engine mainly through the pilot outlet 12 2 3 MAIN SYSTEM The main system feeds fuel to the engine at medium and high speed operation Fuel is metered by the main jet and flows into the main nozzle Air metered by the main air jet is mixed with fuel through the bleed ho...

Page 53: ... 52 FUEL SYSTEM OUTLINE FLOAT CHAMBER FUEL NEEDLE VALVE FLOAT PILOT OUTLET BYPASS PILOT AIR JET CHOKE VALVE AIR INTAKE PORT MAIN AIR JET MAIN NOZZLE PILOT JET FLOAT MAIN JET ...

Page 54: ...re is not correct This is usually caused by clogged jets air passages and fuel passages or by variations in the fuel level To get the best possible performance from the carburetor ensure that the each passages are kept clean so that air and fuel can flow freely through them 1 2 4 10 8 7 3 9 11 12 13 19 23 16 14 15 20 21 17 18 5 6 22 ...

Page 55: ...he screw and remove the float chamber body 2 Remove the gasket from the body 3 Remove the main jet from the body 4 When reassembling the main system be sure to fasten the main jet firmly to the body otherwise the fuel concentration in the fuel air mixture may become too rich leading to engine malfunction 5 The tightening torque of the screw is 9 N m 90 kgf cm 6 5 ft lb Be sure not to forget to mou...

Page 56: ...y controlling the reel with the thumbs of both hands unwind the reel gently until the rotation of the reel stops Before starting the disassembly make sure to wear the protective glasses WARNING The spring power is at its maximum when the rope is fully extracted Do not put off your hand nor loosen the pressure of your finger suddenly WARNING Set screw Friction plate Friction spring Ratchet Reel Cas...

Page 57: ...o that the receiving area of the reel is within the area illustrated in Figure 13 2 B 2 Assemble the friction spring to the shaft in the case 3 Insert the legs of friction plate 2 places in ratchet holes Figure 13 2 C 3 Tighten the center screw 2 people required for this step 1 Adjust the tip of center shaft to the hole of friction plate and compress the friction spring by pushing the friction pla...

Page 58: ...he rope end through the rope guide to the rope hole on the reel and make a knot as shown in Figure 13 2 D 2 Put the rope end knot in the reel paying attention that it will not touch the case Figure 13 2 E 3 Hold the rope firmly with the hand at the position about 50cm from the rope guide and keep the rope slightly pull so that the rope will not be wound in 4 Release the hand of the reel gently and...

Page 59: ...s If the problem is not solved wind the reel 1 to 2 turns In this case check that the spring is not over stressed C The spring comes off with a sound and the starter rope cannot be wound in the reel reassemble the starter from the beginning 13 4 OTHER GUIDES 1 When the spring jumps out of the reel With a thin wire make a ring whose diameter is smaller than spring housing Hook the outer end of the ...

Page 60: ...he working equipment from heating up Be sure to keep the engine room temperature below 50 C all year round and to prevent the accumulation of hot air in the engine room 14 3 EXHAUST EQUIPMENT Exhaust gas is noxious When operating the engine indoors make sure that exhaust gases are discharged outdoors However if the exhaust pipe is long resistance increases and this lowers engine output Therefore t...

Page 61: ...y of the machine Install the engine pulley as close to the engine as possible If possible span the belt horizontally Disengage the load when starting the engine A belt tensioner or similar should be installed if no clutch is used 14 5 2 FLEXIBLE COUPLING When using a flexible coupling run out and misalignment between the driven shaft and the engine shaft should be minimized The permissible margin ...

Page 62: ...ressure due to a long exhaust pipe 15 TROUBLESHOOTING Problem and possible cause Remedy Starting diffi culties 1 Ignition system problems 1 Spark plug Improper spark plug gap Insulation defect Carbon deposits Adjust the gap Replace Clean 2 Ignition coil Insulation defect or discontinuity Poor contact or broken wire Replace Repair or replace 3 Improper air gap between ignition coil and flywheel Adj...

Page 63: ...Check and retighten joints 4 Poor quality gasoline or water in gasoline Replace 4 Low air intake volume 1 Air cleaner clogged Clean or replace 2 Throttle valve malfunction Repair or replace Overheat 1 Engine 1 Cooling air flow obstructed at inlet or cylinder baffle portion Clean 2 Poor quality engine oil Replace 3 Lean fuel air mixture Check and adjust carburetor 4 Excessive back pressure of exhau...

Page 64: ...oat chamber Repair or replace 3 Choke does not open fully Repair or replace 2 Engine core components 1 Low compression Check and repair 2 Overcooling Check and adjust load and or engine speed Abnormal engine noise 1 Ignition system problems 1 Loose ignition system wiring Inspect and tighten 2 Improper or faulty spark plug Clean or replace 2 Fuel system problems 1 Lean or rich fuel air mixture Clea...

Page 65: ... gap Replace motor brush holder or armature OK OK OK NG NG NG NG NG NG There is any contact failure of starter magnetic switch Please replace OK OK Normal rotation Engine does not start OK NG Too slow Check battery charged state and battery terminal connection or corrosion for any abnormality Check viscosity of engine oil for any abnormality Replace the starter with a new one and check if it runs ...

Page 66: ... battery when voltage is lower than 12 4V or specific gravity is lower than 1 22 at 20 C 2 If the wiring and battery are normal remove the starter and go to 3 Checking of pinion operation 3 Checking of pinion operation Check if the pinion operates or sound of magnetic switch contactor is heard If the pinion does not operate or magnetic switch sound is not heard check continuity of each coil of mag...

Page 67: ...tarter pinion and ring gear RING GEAR PINION GEAR 1 Remove the starter and check pinion and ring gear end faces If worn replace the pinion and ring gear 2 In case of sliding fault of the pinion correct it 3 If shift lever or spring is deformed replace it 3 Both starter and engine run but the engine does not start Check if the rotation speed is normal or slow If slow check the battery and engine oi...

Page 68: ...DIMENSIONS AND LIMITS OF USE 16 STANDARD REPAIR TABLES ITEM STD Limit CYLINDER HEAD Flatness Intake exhaust valve seat contact width Intake exhaust valve guide inner diameter 0 05 0 002 0 1 0 004 Intake Exhaust 0 7 1 0 0 0276 0 0394 Intake Exhaust 5 500 5 518 0 2165 0 2172 Rocker arm pin outer diameter Rocker arm pin support inner diameter Pin outer diameter D1 D2 5 970 5 980 0 235 0 235 5 9 0 232...

Page 69: ...ameter reached to 0 1 0 004 First reboring 75 250 75 269 2 9626 2 9633 Ditto Second reboring 75 500 75 519 2 9724 2 9732 Ditto Less than 0 01 0 0004 Less than 0 015 0 0006 PISTON Outer diameter at skirt in thrust direction Standard 74 980 75 000 2 9520 2 9527 74 89 2 9484 Oversize 0 25 75 230 75 250 2 9618 2 9626 75 14 2 9583 Oversize 0 50 75 480 75 500 2 9717 2 9724 75 39 2 9681 Unit mm in ...

Page 70: ...er at skirt Piston ring end gap Top 0 035 0 080 0 0014 0 0031 0 15 0 0059 Oil ring three piece 0 0100 0 205 0 0004 0 0081 17 991 18 009 0 7083 0 7090 18 035 0 7224 17 992 18 000 0 7083 0 7087 17 960 0 7071 0 065 0 104 0 0026 0 0041 0 25 0 010 Top 0 1 0 3 0 0039 0 0118 1 5 0 0591 Oil ring 0 2 0 7 0 0078 0 0276 1 5 0 0591 Unit mm in ...

Page 71: ...de clearance 34 500 34 516 1 3386 1 3392 34 1 1 3425 0 020 0 049 0 0008 0 0019 0 2 0 0078 18 010 18 021 0 7091 0 7095 18 08 0 7118 0 010 0 029 0 0004 0 0011 0 12 0 0047 0 100 0 780 0 0040 0 307 1 0 0 0394 CRANKSHAFT Crank pin outer diameter 34 467 34 480 1 3570 1 3575 34 35 1 3524 Journal outer diameter D1 29 991 30 000 1 1807 1 1811 D2 29 988 29 997 1 1806 1 1810 D1 D2 Unit mm in ...

Page 72: ...outer diameter D3 D4 8 953 8 975 0 3525 0 3533 8 95 0 3524 INTAKE EXHAUST VALVES Valve stem outer diameter Clearance between valve stem and valve guide Valve clearance in cold state Intake 5 440 5 455 0 2142 0 2148 5 35 0 2106 Exhaust 5 426 5 444 0 2136 0 2143 5 35 0 2106 Intake 0 045 0 078 0 0018 0 0031 0 3 0 0118 Exhaust 0 056 0 092 0 0022 0 0036 0 3 0 0118 Intake 0 11 0 16 0 0043 0 0063 Exhaust...

Page 73: ... 0 0787 CHAIN LENGTH 307 1 12 0906 310 6 12 2284 160N 16kgf F L L Compression pressure kg cm2 500 rpm 5 0 Fuel consumption Continuous load 3600 rpm L Hr 3 0 Lubricant Capacity L 1 0 Efficacy mL 500 Consumption mL Hr 8 13 Oil consumption has been measured under following condition Good break in operation has been finished Oil 10W 30 Grade SE Load Continuous load 3600 rpm Unit mm in ...

Page 74: ...bolts 28 0 30 0 280 300 20 3 21 7 M8 35 flange bolt 17 0 19 0 170 190 12 3 13 7 Connecting rod cap bolts 17 0 20 0 170 200 12 3 14 5 Flywheel nut 59 0 64 0 590 640 42 7 46 3 Main bearing cover bolts 22 0 24 0 220 240 16 2 17 7 Spark plug New 12 0 15 0 120 150 8 7 10 8 Re tightening 23 0 27 0 230 270 16 6 19 5 Muffler nut 18 0 22 0 180 220 13 0 15 9 Ignition coil 7 0 9 0 70 90 5 1 6 5 ...

Page 75: ... dangerous 3 Looseness can result in vibration and accidents 4 Running the engine with insufficient oil can result in serious problems including engine seizure 5 A clogged air cleaner can cause power loss and malfunction 17 2 INSPECTION AND MAINTENANCE AFTER THE FIRST 20 HOURS MAINTENACE ITEMS REASON REMARKS 1 Change the crankcase oil 1 Sludge is deposited during running in 17 3 INSPECTION AND MAI...

Page 76: ... correct the engine parts replacing if necessary 2 Replace the piston rings 3 Replace the fuel hose 1 Dirty misaligned or worn parts can cause low power output and engine malfunction 2 Faulty piston rings can cause low output power and engine malfunction 3 To prevent fuel leakage and attendant dangers 17 8 ENGINE STORAGE 1 Carry out the maintenance jobs described in step 16 1 above 2 Drain fuel fr...

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