Yamaha 2014 MT-07, Service Manual

Page: 343 / 564

CONNECTING RODS AND PISTONS
5-78
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a. Measure cylinder bore with the cylinder bore
gauge.
TIP
Measure cylinder bore 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 “D” 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 replace the piston and piston rings as a
set.
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EAS30748
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
80.000–80.010 mm (3.1496–
3.1500 in)
Taper limit
0.050 mm (0.0020 in)
Out of round limit
0.050 mm (0.0020 in)
Cylinder bore = maximum of D
1
–D
6
Taper limit = maximum of D
1
or D
2
– maximum of
D
5
or D
6
Out of round limit = maximum of D
1
, D
3
or D
5
–
minimum of D
2
, D
4
or D
6
Diameter
79.970–79.985 mm (3.1484–
3.1490 in)
a. 8.0 mm (0.31 in) from the bottom edge of the
piston
Piston-to-cylinder clearance =
Cylinder bore – Piston skirt diameter
Top ring
Ring side clearance
0.030–0.065 mm (0.0012–0.0026
in)
Limit
0.115 mm (0.0045 in)
Ring side clearance
0.020–0.055 mm (0.0008–0.0022
in)
Limit
0.115 mm (0.0045 in)
D
a