Yamaha WR125R 2009 Service Manual page 215

2. Install:
• Piston "1"
• Piston pin "2"
• Piston pin clips "3"
TIP
• Apply engine oil to the piston pin.
• Make sure the punch mark "a" on the piston
points towards the exhaust side of the cylinder.
• Before installing the piston pin clips, cover the
crankcase opening with a clean rag to prevent
the clips from falling into the crankcase.
a
3. Lubricate:
• Piston
• Piston rings
• Cylinder
(with the recommended lubricant)
Recommended lubricant
Engine oil
4. Offset:
• Piston ring end gaps
New
1
2
3 New
CYLINDER AND PISTON
e
a. Top ring
b. Upper oil ring rail
c. Oil ring expander
d. Lower oil ring rail
e. 2nd ring
f. 20 mm (0.79 in)
A. Intake side
5. Install:
• Dowel pins
• Cylinder gasket
• Cylinder "1"
TIP
• While compressing the piston rings with one
hand, install the cylinder with the other hand.
• Pass the timing chain and timing chain guide
(intake side) through the timing chain cavity.
1
5-28
120 a
120 120
f f
d b
c
A
New