Yamaha Star XVS13AA(C) 2011, Service Manual

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CYLINDERS AND PISTONS
5-44
b. If out of specification, rebore or replace the
cylinder, and replace the piston and piston
rings as a set.
c. Measure the 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
The following procedure applies to all of the pis-
ton 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 clearance,
eliminate any carbon deposits from the piston
ring grooves and piston rings.
2. Install:
• Piston ring
(into the cylinder)
TIP
Level the piston ring in the cylinder with the pis-
ton crown.
Piston
Diameter D
99.955–99.970 mm (3.9352–
3.9358 in)
b. 8 mm (0.31 in) from the bottom edge of the
piston
• Piston-to-cylinder clearance =
Cylinder bore “C” -
Piston skirt diameter “P”
Piston-to-cylinder clearance
0.030–0.055 mm (0.0012–0.0022
in)
Limit
0.15 mm (0.0059 in)
Piston ring
Top ring
Ring side clearance
0.030–0.080 mm (0.0012–
0.0032 in)
Limit
0.130 mm (0.0051 in)
2nd ring
Ring side clearance
0.030–0.070 mm (0.0012–
0.0028 in)
Limit
0.130 mm (0.0051 in)