Yamaha 2005 YP400T, Service Manual

Page: 236 / 390

5 - 32
ENG
CYLINDER AND PISTON
2. Measure:
• piston-to-cylinder clearance
▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼
a. Measure cylinder bore “ C ” with the cylinder
bore gauge.
NOTE:
_
Measure cylinder bore “ C ” by taking side-to-
side and front-to-back measurements of the
cylinder. Then, find the average of the mea-
surements.
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 ”
83.000 ~ 83.010 mm
(3.2677 ~ 3.2681 in)
Taper limit “ T ” 0.05 mm (0.002 in)
“ C ” = maximum of D
1
~ D
2
“ T ” = maximum of D
1
or D
2
– maximum of
D
5
or D
6
Piston size “ P ”
Standard
82.930 ~ 82.945 mm
(3.2650 ~ 3.2656 in)
Piston-to-cylinder clearance =
Cylinder bore “ C ” –
Piston skirt diameter “ P ”
Piston-to-cylinder clearance
0.060 ~ 0.075 mm
(0.0024 ~ 0.0030 in)
<Limit>: 0.15 mm (0.0059 in)
Downloaded
from www.ScooterTime.net