Yamaha TT-R50E Owner's Service Manual page 236

CYLINDER AND PISTON
2. Measure:
• Piston-to-cylinder clearance
Measurement steps:
1st step:
• Measure the cylinder bore "C" with a cylin-
der bore gauge.
a 10 ~ 15 mm (0.39 ~ 0.59 in) from the top of
the cylinder
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.
Cylinder
bore "C"
• If out of specification, replace the cylinder,
and replace the piston and piston rings as
set.
2nd step:
• Measure the piston skirt diameter "P" with
a micrometer.
a 5 mm (0.20 in) from the piston bottom edge.
Standard
• If out of specification, replace the piston
and piston rings as a set.
3rd step:
• Calculate the piston-to-cylinder clearance
with following formula:
Piston-to-cylinder clearance =
Cylinder bore "C" –
Piston skirt diameter "P"
Piston-to-cylinder clearance:
0.030 ~ 0.040 mm
(0.0012 ~ 0.0016 in)
<Limit>: 0.15 mm (0.0059 in)
• If out of specification, replace the cylinder,
and replace the piston and piston rings as
set.
4 - 25
ENG
Standard
35.995 ~ 36.015 mm
(1.4171 ~ 1.4179 in)
X + Y
C =
2
Piston size P
35.960 ~ 35.980 mm
(1.4157 ~ 1.4165 in)
Wear
limit
36.05 mm
(1.419 in)