Yamaha 2008 YZF-R6X, Service Manual

Page: 268 / 434

CONNECTING RODS AND PISTONS
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a. Measure cylinder bore “C” with the cylinder
bore gauge.
NOTE:
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.
b. If out of specification, rebore or replace the
cylinder, and replace the piston and piston
rings as a set.
c. Measure piston skirt diameter D “a” with
the micrometer.
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.
f. If out of specification, rebore or 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.
NOTE:
Before measuring the piston ring side clear-
ance, eliminate any carbon deposits from the
piston ring grooves and piston rings.
Bore
67.000–67.010 mm (2.6378–
2.6382 in)
Taper limit
0.050 mm (0.0020 in)
Out of round limit
0.050 mm (0.0020 in)
“C” = maximum of D
1
–D
6
“T” = maximum of D
1
or D
2
- maximum of D
5
or D
6
“R” = maximum of D
1
, D
3
or D
5
- minimum of
D
2
, D
4
or D
6
Piston
Diameter D
66.975–66.990 mm (2.6368–
2.6374 in)
b. 10 mm (0.39 in) from the bottom edge of
the piston
• Piston-to-cylinder clearance =
Cylinder bore “C” -
Piston skirt diameter “D”
Piston-to-cylinder clearance
0.010–0.035 mm (0.0004–
0.0014 in)
Limit
0.05 mm (0.0022 in)
Piston ring
Top ring
Ring side clearance
0.030–0.065 mm (0.0012–
0.0026 in)
2nd ring
Ring side clearance
0.020–0.055 mm (0.0008–
0.0022 in)