Yamaha 2004 WR250FS Owner's Service Manual page 170

a d
45˚
135˚ 135˚
c b
3
New
CYLINDER AND PISTON
2. Position:
• Top ring
• 2nd ring
• Oil ring
a Top ring end
b 2nd ring end
c Oil ring end (upper)
d Oil ring
e
e Oil ring end (lower)
3. Install:
• Piston 1
• Piston pin 2
• Piston pin clip 3
NOTE:
• Apply engine oil onto the piston pin and pis-
ton.
• 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.
• Install the piston pin clips with their ends fac-
ing downward.
Cylinder
1. Lubricate:
• Piston
• Piston ring
• Cylinder
NOTE:
Apply a liberal coating of engine oil.
2. Install:
• Dowel pin 1
• O-ring 2
NOTE:
Apply the lithium soap base grease on the O-
ring.
4 - 48
ENG
Offset the piston ring end gaps as shown.
New
New