Yamaha XVS250 2001, Service Manual

Page: 210 / 332

5-29
CYLINDERS AND PISTONS
ENG
NOTE:
X + Y
2
C =
2. Measure:
piston-to-cylinder clearance
a. Measure cylinder bore “C” with the cylinder
bore gauge.
a 45 mm from the top of the cylinder
Measure cylinder bore “C” by taking side-to-
side and front-to-back measurements of the cyl-
inder. Then, find the average of the measure-
ments.
Standard
Wear
limit
Cylinder
bore C:
48.990 49.030 mm 49.130 mm
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
micrometer.
b 3 mm from the bottom edge of the piston.
Piston size P
Standard 48.965 49.005 mm
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
0.02 0.03 mm
<Limit>: 0.15 mm
f. If out of specification, replace the cylinder, and
replace the piston and piston rings as a set.