Removal; Inspection - Yamaha RST90GTY Service Manual

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43
CRANKCASE

REMOVAL

1. Remove:
• Crankcase bolts
TIP
• Place the engine upside down.
• Loosen the bolts in decreasing numerical order of
the embossed numbers on the crankcase.
• Loosen each bolt 1/4 of a turn at a time. After all
of the bolts are fully loosened, remove them.
2. Remove:
• Lower crankcase
NOTICE
Tap on one side of the crankcase with a soft-
face hammer. Tap only on reinforced portions
of the crankcase, not on the crankcase mating
surfaces. Work slowly and carefully and make
sure that the crankcase halves separate evenly.

INSPECTION

1. Inspect:
• Crankcase:
Cracks/damage → Replace.
TIP
• Thoroughly wash the crankcase halves in a mild
solvent.
• Thoroughly clean all the gasket surfaces and
crankcase mating surfaces.
• Oil delivery passages
Obstruction → Blow out with compressed air.
2. Inspect:
• Timing chain
• Oil pump drive chain
Damage/stiffness → Replace the chain and
sprocket as a set.
3. Inspect:
• Timing chain guide (intake side)
• Timing chain guide (exhaust side)
Damage/wear → Replace the timing chain
guide(-s).
ENG