Yamaha TMAX XP500F 2015, Руководство по обслуживанию, Страница: 270 / 478

CYLINDER AND PISTONS
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b. If out of specification, replace the cylinder,
piston and piston rings as a set.
c. Measure piston skirt diameter “a” 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,
piston and piston rings as a set.
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EAS30292
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.
2. Install:
• Piston ring
(into the cylinder)
TIP
Use the piston crown to level the piston ring near
the bottom of the cylinder where the cylinder
wear is lowest.
3. Measure:
• Piston ring end gap
Out of specification
→
Replace the piston ring
set.
TIP
The oil ring expander spacer’s end gap cannot
be measured. If the oil ring rail’s gap is exces-
sive, replace all three piston rings.
b. 9.0 mm (0.35 in) from the bottom edge of the
piston
Piston
Diameter
67.975–67.990 mm (2.6762–
2.6768 in)
Piston-to-cylinder clearance =
Cylinder bore -
Piston skirt diameter
Piston-to-cylinder clearance
0.010–0.035 mm (0.0004–0.0014
in)
Piston ring
Top ring
Ring side clearance
0.030–0.065 mm (0.0012–
0.0026 in)
Limit
0.100 mm (0.0039 in)
2nd ring
Ring side clearance
0.020–0.055 mm (0.0008–
0.0022 in)
Limit
0.100 mm (0.0039 in)