Yamaha BEARTRACKER YFM250XC, Service Manual

Page: 165 / 398

4 - 67
ENG
ENGINE ASSEMBLY AND ADJUSTMENT
CYLINDER HEAD ASSEMBLY, CYLINDER
AND PISTON
1.Install:
●
Piston 1
●
Piston pin 2
●
Piston pin clips 3
NOTE:
●
The arrow 4 on the piston must point to
the front of the engine.
●
Before installing the piston pin clip, cover
the crankcase with a clean towel or rag so
you will not accidentally drop the pin clip
and material into the crankcase.
WARNING
Always use a new piston pin clip.
2.Apply:
●
4-stroke engine oil
To the piston pin, piston ring grooves and
piston skirt areas.
3.Install:
●
Gasket 1 (cylinder)
●
Dowel pins 2
●
O-ring 3
●
O-ring 4 (to cylinder)
WARNING
Always use new gasket and O-ring.
4.Offset the piston ring end gaps as shown.
NOTE:
●
Be sure to check the manufacturer's
marks or numbers stamped on the rings
are on the top side of the rings.
●
Before installing the cylinder, apply a lib-
eral coating of 4-stroke engine oil to the
piston rings.
1 Top ring
2 Oil ring (lower rail)
3 2nd ring
4 Oil ring (upper rail)
4