Checking The Cylinder And Piston - Yamaha XF50W Service Manual

CYLINDER AND PISTON
EAS00255

CHECKING THE CYLINDER AND PISTON

1. Check:
• piston wall
• cylinder wall
Vertical scratches
the cylinder, and replace the piston and
piston rings as a set.
2. Measure:
piston-to-cylinder clearance
• • • • • • • • • • • • • • • • • • • • • • •
a. Measure cylinder bore "C" with the cylinder
bore gauge.
NOTE:
Measure cylinder bore "C" by taking side-to-side
and front-to-back measurements of the cylinder.
Then, find the average of the measurements.
Cylinder bore "C"
Taper limit "T"
Out-of-round "R"
"C" = maximum of D
"T" = maximum of D or D
"R" = maximum of D
or D
6
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 5mm(0.1969in) from the bottom edge of the
piston
Standard
d. If out of specification, replace the piston and
piston rings as a set.
5-33
ENG
-* Rebore or replace
38.000 ~ 38.010mm
(1.4961 ~ 1.4965in)
0.05mm (0.0020in)
0.05mm (0.0020in)
~ D
- maximum of D or D
, D or D - minimum of D
1 3 5 2
Piston size "P"
37.975 ~ 37.990mm
(1.4951 ~ 1.4957in)
, D
4