Maico SQUARE BARREL, Service Manual

Page 1: ...se to tighten counter clockwise to loosen SQUARE BARREL ENGINE SECTION NOTE ALL THREADS ARE RIGHT HAND Clockwise to tighten counter clockwise to loosen MAICO Service Manual Square Barrel Engine Manual...

Page 2: ...al coil The coil is located under the gasoline tank I Preparation For Disassembly Of The Engine 1 All dirt mud dust and foreign material must be thoroughly re moved from the exterior of the en gine as...

Page 3: ...d pull through the case removing the rubber grommet 11 Remove the ignition cover me dium blade screw driver Not necessary for transmission re pair 12 Remove the three screws holding the magneto housin...

Page 4: ...screw driver Bmm wrench impact slide hammer puller We recommend the use of a slide hammer puller as shown 15 Remove cylinder head 13mm socket www maicowerk com Courtesy of vintagemaico gmail com Squa...

Page 5: ...DC and remove the cylinder 17 Remove pin clips needle nose pliers Push pin through and remove piston and bearing Note the shop towel in the top of cases to keep foreign objects from falling into the l...

Page 6: ...18 Place engine in engine stand with clutch cover up www maicowerk com Courtesy of vintagemaico gmail com Square Barrel Engine Manual Service Manual...

Page 7: ...the total deivation in the cylinder is greater than 006 inch from a new piston A new piston shall have 002 inch clearance between piston and cylinder wall measured at bottom of skirt The machine will...

Page 8: ...gine in the frame lay the machine over with the right side down Pull the plastic transmission vent hose out of the case just above the chain Turn the hose 1800 so that transmission oil will not run o...

Page 9: ...clutch plates clutch guide and note direction of fiber plate and spring stack up 2 Clutch spring height new 075 replace 070 www maicowerk com Courtesy of vintagemaico gmail com Square Barrel Engine M...

Page 10: ...weight model uses 18 springs stacked as shown above 25 Clutch spring heavy 360 400 Place two springs face to face then add two more springs one on each side making a set of 4 springs Use 18 springs ma...

Page 11: ...400 only One fiber plate Thickness new Thickness replace Thickness new Thickness replace 080 Thickness new Thickness replace Note When all fiber clutch is used this plate will have no wear Check for f...

Page 12: ...lutch plates shall be installed to throw the oil out LUTCHES 27a 250 360 fiber clutch 5 fiber plates steel plates 18 to 20 springs double 7b 250 OO steel clutch 20 springs double OO 501 big clutch Fir...

Page 13: ...wn may go either on top or under the spring washers 27d Second design bip clutch used in all 1972 400 SOlcc models S steel splined plates 6 fiber plates 1 terminal plate The narrow machined ring goes...

Page 14: ...7e This is the engine flywheel used on the 501 only NOTES TYP CAL TO ALL CLUTCP ES _ Note The clutch lates shall be installed to throw the oil out Note The clutch throwout bearing requires 14 ball bea...

Page 15: ...clutch nut comes loose the transmission will engage two gears at once 29 Remove clutch center special clutch holding tool and 17mm socket Note Removing the clutch center without the Special clutch too...

Page 16: ...h case remove bronze bush Remove clutch case an primary chain and clutch thrust washer Note condition if bent or grooved replace washer www maicowerk com Courtesy of vintagemaico gmail com Square Barr...

Page 17: ...lock tab from engine sprocket nut chizel and hammer 501cc not shown reassembling grease side of engine sprocket Do not g2ease lock washer Note the pin that keeps the flywheels from rotating The pin is...

Page 18: ...ng 34 Remove kick starter shaft and spring by winding spring and lifting straight up 35 250 and 360 models have eight internal case screws Large blade screw driver 6 Late model 250 all 400 s and 501 s...

Page 19: ...ywheels heat to 450 5000 F in an Do not use a torch 37 Remove spring from hook rachet needle nose pliers 38 Remove left hand case by hand and rawhide hammer 39 Remove crank shaft assembly by hand 40 C...

Page 20: ...475 2 490 inches This dimension should be used as a reference only as the measure ment of the side clearance of the rod is the only accurate method 43 Remove shifting fork spindle by hand Check to see...

Page 21: ...46 Remove lay shaft and shifting fork from upper scroll CHECK to see if the shifting fork on the lay shaft is not touching second gear on the main shaft If it is touching grind for clearance www maic...

Page 22: ...lay shaft Close Ratio 1 2 3 4 Main 17 20 22 22 Teeth Lay 20 18 16 13 Teeth 1 99 1 52 1 23 1 0 Ratio to 1 Wide Ratio 1 2 3 4 Main 14 18 21 Teeth Lay 23 19 1 Teeth 2 78 1 79 1 29 1 0 Ratio Primary Rati...

Page 23: ...otor cycle shop performes this operation The seal land must be checked for any roughness caused by race removal 56 The engine is now torn down far enough for major servicing Do not d sassemble any fur...

Page 24: ...k and re taining spring 58 Removing the circlip from the shifting pawl 59 Removing the shifting pawl 60 Removing the pawl spring www maicowerk com Courtesy of vintagemaico gmail com Square Barrel Engi...

Page 25: ...TECHNICAL SECTION TECHNICAL SECTION www maicowerk com Courtesy of vintagemaico gmail com Square Barrel Engine Manual Service Manual...

Page 26: ...d shift pawl stud are not normally removed however if worn they are available from Maieo parts dis tributor 62 Fuel tap assy 63 Ignition point assy 61 Shift earn bush and shift pawl stud are not norma...

Page 27: ...oot starter assembly 66 Ignition side assembly showing engine seal roller bearing and oil seal 501 engine seals are external to the main bearings www maicowerk com Courtesy of vintagemaico gmail com S...

Page 28: ...7 Drive side assembly showing seal and ball bearing 67 www maicowerk com Courtesy of vintagemaico gmail com Square Barrel Engine Manual Service Manual...

Page 29: ...nut 35 45 foot Ibs Counter shaft nut 40 50 foot lbs 68 TECHNICAL DATA Engine Ignition 360cc SOlce 12 1 Two stroke single isplacement Compression ratio ruel Lubrication cylinder engine 250cc OOcc 247cc...