Yamaha 2004 YXR660 Service Manual page 161

CYLINDER AND PISTON
Cylinder
bore "C"
b. If out of specification, rebore or replace the
cylinder, and replace the piston and piston
rings as a set.
2nd step:
a. Measure piston skirt diameter "P" with a
micrometer.
b 2.5 mm (0.10 in) from the piston bottom edge
Piston skirt diameter "P"
Standard
If out of specification, replace the piston and
b.
piston rings as a set.
3rd step:
a. Find the piston-to-cylinder clearance with
the following formula.
Piston-to-cylinder clearance =
Cylinder bore "C" –
Piston skirt diameter "P"
Piston-to-cylinder clearance
0.050 ~ 0.070 mm
(0.0020 ~ 0.0028 in)
<Limit>: 0.15 mm (0.0059 in)
b. If out of specification, rebore or replace the
cylinder, and replace the piston and piston
rings as a set.
L LLL L LLL L L LLL
4 - 35
ENG
Standard Wear limit
100.005 ~
100.055 mm 100.10 mm
(3.9372 ~ (3.9410 in)
3.9392 in)
X + Y
C =
2
99.945 ~ 99.995 mm
(3.9348 ~ 3.9368 in)
L L LLL L L LLL L L LLL L LLL