11.CRANKCASE/CRANKSHAFT
11-3
SERVICE INFORMATION
GENERAL INSTRUCTIONS
• This section covers crankcase separation to service the crankshaft. The engine must be removed
for this operation.
• The following parts must be removed before separating the crankcase.
−Cylinder head (
Ö
Chapter 7 (90cc/70cc/50cc-4T))
−Cylinder/piston (
Ö
Chapter 8)
−Drive and driven pulleys (
Ö
Chapter 9)
−A.C. generator (
Ö
Chapter 14)
−Starter clutch (
Ö
Chapter 16)
−Oil pump (
Ö
Chapter 4)
SPECIFICATIONS (90cc/70cc/50cc-4T) mm (in)
Item
Service Limit
Connecting rod small end free play
0.05~0.4 (0.002~0.016) 0.6 (0.024)
Connecting rod big end radial clearance
0~0.008 (0~0.00032) 0.05 (0.002)
Run out
⎯ 0.1 (0.004)
SPECIFICATIONS (50cc-2T) mm (in)
Item
Service Limit
Connecting rod big end side clearance
⎯ 0.6 (0.024)
Connecting rod big end radial clearance
⎯ 0.04 (0.0016)
Run out A/B
⎯ 0.1/0.15 (0.004/0.006)
TORQUE VALUES
Crankcase bolt 10 N-m (1 kgf-m, 7 lbf-ft)
Cam chain tensioner slipper bolt (90cc/70cc/50cc-4T) 10 N-m (1 kgf-m, 7 lbf-ft)
SPECIAL TOOLS (50cc-2T)
Crankcase puller A120E00026
Universal bearing puller A120E00030
Crankshaft install tool A120E00016
Crankcase assembly tool A120E00024
Oil seal and bearing install tool A120E00014
TROUBLESHOOTING
Abnormal engine noise
• Excessive crank journal bearing play
• Excessive crankpin bearing play
• Excessive transmission bearing play