Yamaha VINO XC50V, Service Manual, Page: 178 / 298

ENG
5-29
CYLINDER AND PISTON
EAS00261
CHECKING THE CYLINDER AND PISTON
1. Check:
8
piston wall
8
cylinder wall
Vertical scratches
J
Replace the cylin-
der, and the piston and piston rings as a
set.
2. Measure:
8
piston-to-cylinder clearance
*****************************************************
a. Please carry out the following inspections:
8
cylinder
Measure the piston pin in both of its hori-
zontal axis direction a and its right angle
direction b at six positions of A, B, etc.
with a cylinder gauge.
Abrasion=Nax. value - min. value as mea-
sured at those six positions.
When abrasion is beyond limit
J
Replace
it
Standard
38.000 ~ 38.010 mm(1.4961 ~ 1.4965 in)
b. If out of specification, replace the cylinder,
and the piston and piston rings as a set.
c. Measure piston skirt diameter “P” with the
micrometer.
a
5 mm (0.197 in) from the bottom edge of the
piston
Piston size “P”
37.975 ~ 37.990 mm (1.495 ~ 1.496 in)
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
0.010 ~ 0.035 mm (0.0004 ~ 0.0014
in)
<Limit>: 0.15 mm (0.006 in)
f. If out of specification, replace the cylinder,
and the piston and piston rings as a set.
*****************************************************
a
P