Yamaha TT-R50E, Owner'S Service Manual

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ENG
CYLINDER AND PISTON
Piston pin
1. Inspect:
• Piston pin
Blue discoloration/grooves
→
Replace, then inspect the lubrication sys-
tem.
2. Measure:
• Piston pin outside diameter
• Piston pin bore inside diameter
ASSEMBLY AND INSTALLATION
Piston
1. Install:
• Piston rings
(onto the piston)
NOTE:
• Be sure to install the piston rings so that the
manufacturer’s marks or numbers are
located on the upper side of the rings.
• Lubricate the piston and piston rings liberally
with engine oil.
Measurement steps:
• Measure the piston pin outside diameter
a
.
If out of specification, replace the piston
pin.
Outside diameter (piston pin):
11.996 ~ 12.000 mm
(0.4723 ~ 0.4724 in)
<Limit>:11.976 mm (0.4715 in)
• Measure the piston inside diameter
b
.
If out of specification, replace the piston.
Inside diameter (piston):
12.002 ~ 12.013 mm
(0.4725 ~ 0.4730 in)
<Limit>: 12.043 mm (0.4741 in)