Yamaha FZ6RC, Service Manual

Page: 265 / 420

CRANKSHAFT
5-67
EAS24390
CHECKING THE CYLINDER AND PISTON
1. Check:
●
Piston wall
●
Cylinder wall
Vertical scratches
→
Replace the cylinder,
and replace the piston and piston rings as a
set.
2. Measure:
●
Piston-to-cylinder clearance
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a. Measure cylinder bore “C” with the cylinder
bore gauge.
TIP
Measure cylinder bore “C” by taking side-to-side
and front-to-back measurements of the cylinder.
Then, find the average of the measurements.
b. If out of specification, replace the cylinder,
and replace the piston and piston rings as a
set.
c. Measure piston skirt diameter “P” with the mi-
crometer.
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, replace the cylinder,
and the piston and piston rings as a set.
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EAS24430
CHECKING THE PISTON RINGS
1. Measure:
●
Piston ring side clearance
Out of specification
→
Replace the piston
and piston rings as a set.
TIP
Before measuring the piston ring side clearance,
eliminate any carbon deposits from the piston
ring grooves and piston rings.
Bore
65.500 – 65.510 mm
(2.5787 – 2.5791 in)
Wear limit
65.56 mm (2.5811 in)
Taper limit
0.050 mm (0.0020 in)
Out of round limit
0.050 mm (0.0020 in)
“C” = maximum of D
1
– D
6
“T” = maximum of D
1
or D
2
- maximum of D
5
or D
6
“R” = maximum of D
1
, D
3
or D
5
- minimum of D
2
, D
4
or
D
6
Piston size “P”
Standard
65.475
–
65.490 mm
(2.5778
–
2.5783 in)
a. 5 mm (0.20 in) from the bottom edge of the piston
Piston-to-cylinder clearance =
Cylinder bore
“ C ” -
Piston skirt diameter “ P ”
Piston-to-cylinder clearance
0.010 – 0.035 mm
(0.0004 – 0.0014 in)