4-28
ENG
CYLINDERS AND PISTONS
NOTE:
a. Measure cylinder bore “C” with the cylinder
bore gauge.
120 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.
Cylinder bore gauge
Standard 79.00 79.01 mm
Wear limit 79.1 mm
Cylinder bore “C” “C” = X + Y/2
b. If out of specification, replace the cylinder,
and replace the piston and piston rings as a
set.
c. Measure piston skirt diameter “P” with the
micrometer.
a2.0 mm from the bottom edge of the piston.
Piston size “P”
Standard 78.970 78.985
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
0.015 0.040 mm
<Limit> : 0.15 mm
f. If out of specification, replace the cylinder,
and replace the piston and piston rings as a
set.