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11. CRANKCASE/CRANKSHAFT

11-0

MX’er 50

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CRANKCASE/CRANKSHAFT

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SERVICE INFORMATION........................................................ 11-2

TROUBLESHOOTING.............................................................. 11-2

CRANKCASE SEPARATION .................................................... 11-3

CRANKSHAFT REMOVAL....................................................... 11-3

CRANKSHAFT INSPECTION ................................................... 11-4

CRANKSHAFT INSTALLATION.............................................. 11-5

CRANKCASE ASSEMBLY ....................................................... 11-7

Summary of content (9 pages)

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11. CRANKCASE/CRANKSHAFT MX’er 50 SERVICE INFORMATION GENERAL INSTRUCTIONS • This section covers crankcase separation to service the crankshaft. • The following parts must be removed before separating the crankcase. Engine (!Section 6) Driven pulley (!Section 9) Carburetor (!Section 5) A.C. generator (!Section 8) Oil pump (!Section 4) Cylinder head/cylinder (!Section 7) Reed valve (!Section 5) • When the left crankcase must be replaced, remove the following part in addition to the above.
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11. CRANKCASE/CRANKSHAFT MX’er 50 CRANKCASE SEPARATION Remove the crankcase attaching bolts. Bolt Crankcase Puller Attach the crankcase puller on the right crankcase and remove the right crankcase from the left crankcase. Crankcase Puller CRANKSHAFT REMOVAL Attach the crankcase puller on the left crankcase and remove the crankshaft from the left crankcase. °Ø When removing the crankshaft, do it slowly and gently.
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11. CRANKCASE/CRANKSHAFT MX’er 50 Remove the remaining bearing on the crankshaft side using the universal bearing puller. °ØWhen separating the crankcase, the oil seals must be removed. Replace the oil seals with new ones. Universal Bearing Puller CRANKSHAFT INSPECTION Measure the connecting rod big end side clearance. Service Limit: 0.6mm replace if over Measure the connecting rod big end radial clearance at two points in the X and Y directions. Service Limit: 0.
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11. CRANKCASE/CRANKSHAFT MX’er 50 Measure the crankshaft runout. Service Limit A B 0.150mm replace if over 0.100mm replace if over Check the crankshaft bearings for excessive play. The bearings must be replaced if they are noisy or have excessive play. Play Axial CRANKSHAFT INSTALLATION Wash the crankshaft in cleaning solvent and then check for cracks or other faults. °Ø• After check, apply clean engine oil to all moving and sliding parts.
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11. CRANKCASE/CRANKSHAFT Drive a new crankshaft bearing into the right crankcase. MX’er 50 Bearing Outer Driver Handle A Bearing Outer Driver, 37x40mm Bearing Driver Pilot, 17mm Bearing Outer Driver Handle A Drive a new crankshaft bearing into the left crankcase. Bearing Outer Driver, 42x47mm Pilot, 20mm Install the crankshaft into the left crankcase. °Ø • Apply KYMCO ULTRA motor oil or molybdenum disulfide to the crankshaft bearings and connecting rod big end.
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11. CRANKCASE/CRANKSHAFT CRANKCASE ASSEMBLY MX’er 50 Dowel Pins Install the dowel pins and a new gasket to the crankcase mating surface. Assemble the crankcase halves. Crankcase Assembly Tool The distance between the right crankcase oil seal and crankcase surface is about 12.5±0.5 mm. °Ø When installing the oil seal, be careful to press it with even force.
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11. CRANKCASE/CRANKSHAFT MX’er 50 The distance between the left crankcase oil seal and crankcase surface is about 1.0mm. Oil Seal 1.0mm Install and tighten the crankcase attaching bolts. °Ø After assembly, check the crankshaft for smooth operation.