Checking The Piston Rings - Yamaha 2007 XP500 Service Manual

Bore "C"
Bore
66.000–66.010 mm
(2.5984–2.5988 in)
Taper limit "T"
Taper limit
0.050 mm (0.0020 in)
Out of round "R"
Out of round limit
0.050 mm (0.0020 in)
"C"= maximum of D1–D6
"T"= (maximum of D1 or D2)—(maximum of
D5 or D6)
"R" = maximum of D1, D3 or D5 . minimum of
D2, D4 or D6
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 "P" with the mi-
crometer.
Piston size "P"
65.965–65.980 mm
(2.5970–2.5976 in)
a. 9.0 mm (0.35 in) from the bottom edge of the pis-
ton
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
0.020 – 0.045 mm (0.0008 –
0.0018 in)
Limit: 0.15 mm (0.0059 in)
f. If out of specification, rebore or replace the
CYLINDER AND PISTONS
cylinder, and replace the piston and piston
rings as a set.
LLLLLLLLLLLLLLLLLLLLLL
EAS24430

CHECKING THE PISTON RINGS

1. Measure:
Piston ring side clearance
G
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.
Piston ring side clearance
Ring side clearance
0.030–0.065 mm (0.0012–0.0026
in)
Limit
0.100 mm (0.0039 in)
Ring side clearance
0.020–0.055 mm (0.0008–0.0022
in)
Limit
0.100 mm (0.0039 in)
2. Install:
Piston ring
G
(into the cylinder)
NOTE:
Level the piston ring into the cylinder with the
piston crown.
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