Checking The Piston Rings - Yamaha YFZ450S 2003 Service Manual

CYLINDER AND PISTON
f. If out of specification, replace the cylinder,
and the piston and piston rings as a set.
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EBS00250

CHECKING THE PISTON RINGS

1. Measure:
• piston ring side clearance
Out of specification → Replace the piston
and piston rings as a set.
NOTE:
_
Before measuring the piston ring side clear-
ance, eliminate any carbon deposits from the
piston ring grooves and piston rings.
Piston ring side clearance
2. Install:
• piston ring
(into the cylinder)
NOTE:
_
Level the piston ring into the cylinder with the
piston crown.
a 10 mm (0.39 in)
4 - 37
ENG
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Top ring
0.030 ~ 0.065 mm
(0.0012 ~ 0.0026 in)
<Limit>: 0.12 mm (0.0047 in)
2nd ring
0.020 ~ 0.055 mm
(0.0008 ~ 0.0022 in)
<Limit>: 0.12 mm (0.0047 in)
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