Yamaha FJR13AEV(C), Service Manual

Page: 407 / 726

CONNECTING RODS AND PISTONS
5-106
NOTE:
Measure cylinder bore “C” by taking side-to-side
and front-to-back measurements of the cylinder.
Then, find the average of the measurements.
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 clearance,
eliminate any carbon deposits from the piston
ring grooves and piston rings.
Bore
79.000–79.010 mm (3.1102–
3.1106 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
78.965–78.980 mm (3.1089–
3.1094 in)
b. 5 mm (0.20 in) from the bottom edge of the
piston
• Piston-to-cylinder clearance =
Cylinder bore “C” -
Piston skirt diameter “D”
Piston-to-cylinder clearance
0.020–0.045 mm (0.0008–0.0018
in)
Limit
0.12 mm (0.0047 in)
Piston ring
Top ring
Ring side clearance
0.030–0.070 mm (0.0012–
0.0028 in)
Limit
0.120 mm (0.0047 in)
2nd ring
Ring side clearance
0.020–0.060 mm (0.0008–
0.0024 in)
Limit
0.120 mm (0.0047 in)