12. CRANKCASE/CRANKSHAFT ATV 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.
Final reduction removal
· Special tools must be used for crankshaft and crankcase assembly. When separating the
crankcase, the bearing will remain in the crankcase and it should be removed. When,
assembling, drive a new bearing into the crankcase and install a new oil seal.
SPECIFICATIONS
mm (in)
Item Standard Service Limit
Connecting rod big end side
clearance 0.6 (0.024)
Connecting rod big end radial
clearance 0.04 (0.0016)
Crankshaft runout A/B 0.15 (0.006)/0.1 (0.004)
SPECIAL TOOLS
Crankcase puller A120E00026
Universal bearing puller A120E00030
Crankcase assembly tool (left crankcase) A120E00024
Crankcase assembly tool (right crankcase) A120E00016
Oil seal & bearing driver A120E00014
TROUBLESHOOTING
Abnormal engine noise
· Excessive crank journal bearing play
· Excessive crankpin bearing play
· Excessive transmission bearing play
12-2
RAS 
4.7 / 5