Checking The Piston Rings - Yamaha PW50W 2007 Service Manual

CYLINDER HEAD, CYLINDER AND PISTON
"C"= maximum of D
"T"= (maximum of D
or D )
6
b. If out of specification, replace the cylinder,
and replace the piston and piston rings as
a set.
c. Measure piston skirt diameter "D" with the
micrometer.
a 5 mm (0.20 in) from the bottom edge of the piston
Diameter D
39.952-39.972 mm (1.5729-1.5737 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 "D"
Piston-to-cylinder clearance
0.034-0.047 mm (0.0013-0.0019 in)
Limit
0.10 mm (0.0039 in)
f. If out of specification, replace the cylinder,
and replace the piston and piston rings as
set.
LLLLLLLLLLLLLLLLLLLLLLL

CHECKING THE PISTON RINGS

1. Measure:
9 Piston ring side clearance
Out of specification → Replace the piston
and piston rings as a set.
NOTE:
Before measuring the piston ring side clear-
ance, eliminate any carbon deposits from the
piston ring grooves and piston rings.
Piston ring side clearance
Ring side clearance
0.020-0.060 mm (0.0008-0.0024 in)
Limit
0.080 mm (0.0032 in)
5-13
ENG
–D
1 6
or D )-(maximum of D
1 2 5