Yamaha TT-R125EY Service Manual page 128

CYLINDER AND PISTON
• If out of specification, replace the cylinder,
and replace the piston and piston rings as a
set.
Piston pin
1. Inspect:
• Piston pin
Blue discoloration/grooves → Replace,
then inspect the lubrication system.
2. Measure:
• Piston pin-to-piston clearance
Measurement steps:
• Measure the piston pin outside diameter a.
If out of specification, replace the piston pin.
Outside diameter (piston pin):
14.991 ~ 15.000 mm
(0.5902 ~ 0.5906 in)
<Limit>: 14.971 mm (0.5894 in)
• Measure the piston inside diameter b.
If out of specification, replace the piston.
Inside diameter (piston):
15.002 ~ 15.013 mm
(0.5906 ~ 0.5911 in)
<Limit>: 15.043 mm (0.5922 in)
4-35
ENG