Yamaha 5YF2-AE1 Service Manual page 121

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