Installing The Piston - Yamaha YFM4FAR Service Manual

CYLINDER AND PISTON
G
If out of specification, replace the piston.
Piston pin-to-piston clearance:
0.004 ~ 0.024 mm
(0.00016 ~ 0.00094 in)
<Limit>: 0.074 mm (0.0029 in)
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INSTALLING THE PISTON

1.Install:
Piston rings
G
(onto the piston)
NOTE:
Be sure to install the piston rings so that the
G
manufacturer's
located on the upper side of the rings.
Lubricate the piston and piston rings liberally
G
with engine oil.
2.Position:
Top ring
G
2nd ring
G
Oil ring
G
Offset the piston ring end gaps as shown.
a Top ring end
b Oil ring end (upper)
c Oil ring end (lower)
d 2nd ring end
3.Install:
Piston 1
G
Piston pin 2
G
Piston pin clips 3
G
NOTE:
Apply engine oil onto the piston pin, piston
G
ring and piston.
Be sure that the arrow mark a on the piston
G
points to the exhaust side of the engine.
Before installing the piston pin clips, cover
G
the crankcase with a clean rag to prevent the
piston pin clips from falling into the
crankcase.
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ENG
marks or numbers
New
are