Yamaha YFZ450S 2003 Service Manual page 179

CYLINDER AND PISTON
2. Measure:
• piston-to-cylinder clearance
M MMM M MMM M
a. Measure the cylinder bore "C" with a cylin-
der bore gauge.
NOTE:
_
Measure the cylinder bore "C" in parallel to and
right angles to the crankshaft. Then, find the
average of the measurements.
Cylinder bore "C"
Taper limit "T"
Out of round "R"
"C" = Maximum D
"T" = (Maximum D
– (Maximum D
"R" = (Maximum D
– (Minimum D
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 10 mm (0.39 in) from the bottom edge of the pis-
ton
Piston size "P"
Standard
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
4 - 36
ENG
M MMM M M MMM M M MMM M
95.00 ~ 95.01 mm
(3.7402 ~ 3.7406 in)
0.05 mm (0.002 in)
0.05 mm (0.002 in)
or D )
1 2
or D )
5 6
, D or D
1 3 5
, D or D
2 4
94.945 ~ 94.960 mm
(3.7380 ~ 3.7386 in)
0.04 ~ 0.065 mm
(0.0016 ~ 0.0026 in)
<Limit>: 0.10 mm (0.004 in)
M MMM M MMM
)
)
6