Service manual

ENG
4-24
CYLINDER AND PISTON
D 1
D 2
D 3
D 4
D 5
D 6
2. Measure:
• piston-to-cylinder clearance
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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 XN 125 53.700 ~ 53.705 mm
bore “C” XN 150 59.500 ~ 59.505 mm
Taper limit “T” 0.05 mm
Out-of-round “R” 0.05 mm
“C” = maximum of D
1 ~ D2
“T” = maximum of D1 or D2 - maximum
of D
5 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
micrometer.
Piston size “P”
Standard
XN 125 53.670 ~ 53.687 mm
XN 150 59.470 ~ 59.487 mm
Oversize 2
XN 125 53.92 mm
XN 150 59.72 mm
Oversize 4
XN 125 54.17 mm
XN 150 59.97 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
0.025 ~ 0.035 mm
<Limit>: 0.15mm
f. If out of specification, rebore or replace the
cylinder, and replace the piston and piston
rings as a set.
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