Checking The Piston Rings - Yamaha FJR1300AS(X) Service Manual

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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 measurements.
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
"T" = maximum of D
or D
6
"R" = maximum of D
D , D or D
2 4 6
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.
Piston
Diameter D
78.965–78.980 mm (3.1089–
3.1094 in)
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–D
1 6
or D - maximum of D
1 2
, D or D - minimum of
1 3 5
CONNECTING RODS AND PISTONS
MMM
b. 5 mm (0.20 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" -
5
Piston skirt diameter "D"
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.
5-109
Piston-to-cylinder clearance
0.020–0.045 mm (0.0008–0.0018
in)
Limit
0.12 mm (0.0047 in)
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