Yamaha 2002 CS50, Service Manual, Page: 76 / 204

ENG
INSPECTION AND REPAIR
4-13
a. Measure cylinder bore “C” with the cylinder
bore gauge.
NOTE:
Measure cylinder bore “C” by taking side-tosi-
de and front-to-back measurements of the
cylinder.Then, find the average of the measu-
rements.
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.
a 5 mm 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.
f. If out of specification, rebore or replace the
cylinder, and replace the piston and piston
rings as a set.
Piston size “P”
Standard
CS50: 39.952 ~ 39.972 mm
CS50Z: 39.957 ~ 39.977 mm
Piston-to-cylinder clearance=
Cylinder bore “C” -
Piston skirt diameter “P”
Piston-to-cylinder clearance
CS50: 0.034 ~ 0.047 mm
CS50Z: 0.029 ~ 0.042 mm
<Limit>: 0.1 mm
Standard Wear limit
Cylinder
39.99 ~ 40.01 mm 40.1 mm
bore “C”
Taper Limit
– 0.05 mm
“T”
Out of round
– 0.01 mm
“R”
“C” = maximum of D
1
~ D
6
“T” = maximum of D
1
, or D
2
- maximum of
D
5
or D
6
“R” = maximum of D
1
, D
3
or D
5
- minimum
of D
2
, D
4
or D
6