Yamaha WR450F, Owner'S Service Manual

Page: 422 / 794

4 - 51
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
2nd ring end
c
Oil ring end (upper)
d
Oil ring
e
Oil ring end (lower)
45
135 135
a
b c e
d
3. Install:
• Piston
1
• Piston pin
2
• Piston pin clips
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.
4. Lubricate:
• Piston
• Piston rings
• Cylinder
NOTE:
Apply a liberal coating of engine oil.
Cylinder
1. Install:
• Gasket
1
• Cylinder
2
NOTE:
Install the cylinder with one hand while com-
pressing the piston rings with the other hand.
CAUTION:
• Pass the timing chain
3
through the tim-
ing chain cavity.
• Be careful not to damage the timing chain
guide
4
during installation.
2. Install:
• Bolt (cylinder)
3
New
New
New
T
R
.
.
10 Nm (1.0 m · kg, 7.2 ft · lb)