Yamaha TTR90(M), Owner'S Service Manual

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ENG
CYLINDER AND PISTON
2. Position:
●
Top ring
●
2nd ring
●
Oil ring
Offset the piston ring end gaps as
shown.
a
Top ring end
b
Oil ring end (lower)
c
Oil ring end (upper)
d
2nd ring end
3. Install:
●
Piston 1
●
Piston pin 2
●
Piston pin clips 3
NOTE:
●
Apply engine oil onto the piston pin, piston
ring and piston.
●
Be sure that the arrow mark
a
on the piston
points to the exhaust side of the engine.
●
Before installing the piston pin clip, cover the
crankcase with a clean rag to prevent the
piston pin clip from falling into the crankcase.
4. Lubricate:
●
Piston
●
Piston rings
●
Cylinder
NOTE:
Apply a liberal coating of engine oil.
New
Cylinder
1. Install:
●
Cylinder 1
NOTE:
Install the cylinder with one hand while com-
pressing the piston rings with the other hand.
CAUTION:
●
Be careful not to damage the timing chain
damper during installation.
●
Pass the timing chain through the timing
chain cavity.