Installing The Piston And Cylinder - Yamaha RAPTOR YFM125RA Service Manual

EAS24450

INSTALLING THE PISTON AND CYLINDER

1. Install:
• Lower oil ring rail "1"
• Oil ring expander "2"
• Upper oil ring rail "3"
• 2nd ring "4"
• Top ring "5"
TIP
Be sure to install the piston rings so that the
manufacturer's mark or number face up.
2. Install:
• Piston "1"
• Piston pin "2"
• Piston pin clips "3"
TIP
• Apply engine oil to the piston pin.
• Make sure the arrow mark "a" on the piston
points towards the exhaust side of the cylin-
der.
• Before installing the piston pin clip, cover the
crankcase opening with a clean rag to pre-
vent the clip from falling into the crankcase.
3. Install:
• O-ring New
• Dowel pins
• Cylinder gasket
New
New
5-30
CYLINDER AND PISTON
4. Lubricate:
• Piston
• Piston rings
• Cylinder
(with the recommended lubricant)
Recommended lubricant
Engine oil
5. Offset:
• Piston ring end gaps
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. Exhaust side
6. Install:
• O-ring New
(to the cylinder)
• 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.
7. Install:
• Timing chain guide (exhaust side)