ENGINE / TRANSMISSION
Crankcase Disassembly
NOTE: Engine must be removed to perform
crankcase or crankshaft service.
1. Remove engine, cylinder, piston, and stator assembly.
2. Loosen crankcase screws evenly and remove.
Crankshaft Inspection
1. Inspect the crankshaft main bearings and cam chain
sprocket for wear or damage.
NOTE: Due to extremely close tolerances and
minimal wear, the bearings must be inspected
visually, and by feel. Look for signs of discoloration,
scoring or galling. Turn outer race of each bearing.
Bearings should turn smoothly and quietly. The
inner race of each bearing should fit tightly on the
crankshaft. The outer race should be firm with
minimal side to side movement and no detectable up
and down movement.
2. The connecting rod big end bearing is a roller bearing.
Visually inspect connecting rod big end for scoring,
damage or excessive wear. If connecting rod passes visual
inspection, measure radial clearance carefully with
crankshaft clamped in V-blocks at points “A” and a dial
indicator measuring total up and down movement “B”.
Compare to specifications. If clearance is excessive replace
the crankshaft assembly.
3. Separate right crankcase from left by tapping gently with a
soft face hammer evenly around the case as required. Leave
the crankshaft in the left crankcase half. Do not attempt to
remove crankshaft with right case or cam chain will be
3. Inspect the clearance of connecting rod big end and flywheel
by feeling gauge. If clearance is excessive replace the
crankshaft assembly.
Connecting rod clearance limit: 0.4 mm (.016”).
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