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10. CRANKCASE/CRANKSHAFT

10-0

YUP 50

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CRANKCASE/CRANKSHAFT

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SERVICE INFORMATION........................................................ 10-2

TROUBLESHOOTING.............................................................. 10-2

CRANKCASE SEPARATION .................................................... 10-3

CRANKSHAFT REMOVAL....................................................... 10-3

CRANKSHAFT INSPECTION ................................................... 10-4

CRANKSHAFT INSTALLATION.............................................. 10-5

CRANKCASE ASSEMBLY ....................................................... 10-7

1010

Summary of content (9 pages)

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10. CRANKCASE/CRANKSHAFT Torque: 0.8_ 1.
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10. CRANKCASE/CRANKSHAFT YUP 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 5) Driven pulley (Section 9) Carburetor (Section 11) A.C. generator (Section 7) Oil pump (Section 4) Cylinder head/cylinder (Section 6) Reed valve (Section 11) • When the left crankcase must be replaced, remove the following part in addition to the above.
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12. FRAME COVERS CRANKCASE SEPARATION Remove the crankcase attaching bolts. Bolt Attach the crankcase puller on the right crankcase and remove the right crankcase from the left crankcase. 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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10. CRANKCASE/CRANKSHAFT YUP 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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12. FRAME COVERS 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. • Remove all gasket material from the crankcase mating surfaces.
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10. CRANKCASE/CRANKSHAFT Drive a new crankshaft bearing into the right crankcase. YUP 50 Bearing Outer Driver Handle A Bearing Outer Driver, 37x40mm Bearing Driver Pilot, 17mm Drive a new crankshaft bearing into the left crankcase. Bearing Outer Driver Handle A 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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12. FRAME COVERS CRANKCASE ASSEMBLY 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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10. CRANKCASE/CRANKSHAFT YUP 50 Oil Seal The distance between the left crankcase oil seal and crankcase surface is about 1.0mm. 1.0mm Install and tighten the crankcase attaching bolts. °Ø After assembly, check the crankshaft for smooth operation.