Yamaha RAPTOR YFM50S, Service Manual

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4 - 25
ENG
CYLINDER AND PISTON
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.
a
5 mm (0.20 in) from the bottom edge of the pis-
ton
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.
f. If out of specification, rebore or replace the
cylinder, and replace the piston and piston
rings as a set.
▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲▲▲
Cylinder bore “C”
39.000 ~ 39.005 mm
(1.5354 ~ 1.5356 in)
Taper limit “T” 0.05 mm (0.002 in)
Out-of-round “R” 0.01 mm (0.0004 in)
“C” = maximum of D
1
~ D
2
“T” = maximum of D
1
or D
2
–
maximum of D
5
or D
6
“R” = maximum of D
1
, D
3
or D
5
–
minimum of D
2
, D
4
or D
6
Piston size “P”
Standard
38.960 ~ 38.975 mm
(1.5339 ~ 1.5344 in)
Piston-to-cylinder clearance =
Cylinder bore “C” –
Piston skirt diameter “P”
Piston-to-cylinder clearance
0.025 ~ 0.045 mm
(0.0010 ~ 0.0018 in)
<Limit>: 0.15 mm (0.0059 in)