Yamaha FX Nytro FX10MTRAX, Service Manual, Page: 502 / 859

5-60
ENG
CONNECTING RODS AND PISTONS
2nd step:
• Measure piston skirt diameter “P” with the
micrometer.
a
11.0 mm (0.43 in) from the bottom edge of the piston.
• If out of specification, replace the piston and
piston rings as a set.
3rd step:
• Calculate the piston-to-cylinder clearance with
the following formula.
Piston-to-cylinder clearance =
Cylinder bore “C” –
Piston skirt diameter “P”
• If out of specification, replace the crankcase,
and the piston and piston rings as a set.
Piston size (standard) (P):
81.950 ~ 81.965 mm
(3.2264 ~ 3.2270 in)
Piston-to-cylinder clearance:
0.035 ~ 0.060 mm
(0.0014 ~ 0.0024 in)
<Limit>: 0.120 mm (0.0047 in)
3. Measure:
• Piston ring side clearance
Use the thickness gauge 1 .
Out of specification
→
Replace the piston and
piston rings as a set.
NOTE:
Eliminate the carbon deposits from the piston ring
grooves and rings before measuring the side clear-
ance.
Piston rings side clearance:
Top ring:
0.030 ~ 0.070 mm
(0.0012 ~ 0.0028 in)
2nd ring:
0.020 ~ 0.060 mm
(0.0008 ~ 0.0024 in)