Service manual

4 - 66
ENG
CONNECTING RODS AND PISTONS
EB404403
CHECKING THE CYLINDERS AND PISTONS
The following procedure applies to all of
the cylinders and pistons.
1.Check:
• piston wall
• cylinder wall
Vertical scratches → Replace the
crankcases, and the piston and piston
rings as a set.
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 measure-
ments of the cylinder. Then, find the
average of the measurements.
b. If out of specification, replace the
crankcases, and the pistons and pis-
ton rings as a set.
c. Measure piston skirt diameter “P”
with the micrometer.
a 5 mm from the bottom edge of the pis-
ton
d. If out of specification, replace the pis-
ton and piston rings as a set.
Cylinder bore gauge
90890-03017
Cylinder bore “C” 74.000 ~ 74.010 mm
Max. taper “T” 0.05 mm
Out of round “R” 0.05 mm
“C”= maximum of D
1 ~ D6
“T” = maximum of D1, or D2 – maxi-
mum of D
5 or D6
“R” = maximum of D1, D3 or D5 – mini-
mum of D
2, D4 or D6
Micrometer
90890-03008
Piston size “P”
Standard 73.955 ~ 73.970 mm