Checking The Piston Rings - Yamaha YZFR1Y(C) 2009 Service Manual

2. Measure:
• Piston-to-cylinder clearance
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a. Measure cylinder bore "C" with the cylinder
bore gauge.
TIP
Measure cylinder bore "C" by taking side-to-
side and front-to-back measurements of the
cylinder. Then, find the average of the mea-
surements.
Bore
78.000–78.010 mm (3.0709–
3.0713 in)
Taper limit
0.050 mm (0.0020 in)
Out of round limit
0.050 mm (0.0020 in)
Bore = maximum of D
1
Taper limit = maximum of D
mum of D or D
5 6
Out of round limit = maximum of D
- minimum of D , D or D
2 4
b. If out of specification, replace the cylinder,
and replace the piston and piston rings as
a set.
c. Measure piston skirt diameter "P" with the
micrometer.
Piston diameter
77.975–77.990 mm (3.0699–
3.0705 in)
CONNECTING RODS AND PISTONS
–D
2
or D - maxi-
1 2
, D or D
1 3 5
6
a. 12 mm (0.47 in) from the bottom edge of
the piston
d. If out of specification, replace the piston
and piston rings as a set.
e. Calculate the piston-to-cylinder clearance
with the following formula.
Piston-to-cylinder clearance = Cylinder bore
"C" - Piston skirt diameter "P"
Piston-to-cylinder clearance
0.010–0.035
0.0014 in)
Limit
0.150 mm (0.0059 in)
f. If out of specification, replace the cylinder,
and replace the piston and piston rings as
a set.
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EAS24430

CHECKING THE PISTON RINGS

1. Measure:
• Piston ring side clearance
Out of specification → Replace the piston
and piston rings as a set.
TIP
Before measuring the piston ring side clear-
ance, eliminate any carbon deposits from the
piston ring grooves and piston rings.
5-77
mm (0.0004–