CYLINDER AND PISTON
5-34
b. If out of specification, rebore or replace the
cylinder, and replace the piston and the pis-
ton rings as a set.
c. Measure the piston outside diameter D “a” at
the measurement position H “b” with the mi-
crometer.
d. If out of specification, replace the cylinder,
the piston, and the piston rings as a set.
e. Calculate the piston-to-cylinder clearance
with the following formula.
f. If out of specification, replace the cylinder,
the piston, and the piston rings as a set.
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EASB291235
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 clear-
ance, eliminate any carbon deposits from the
piston ring grooves and piston rings.
2. Install:
• Piston rings
TIP
Level the piston ring into the cylinder with the
piston.
3. Measure:
• Piston ring end gap
Out of specification
Replace the piston
ring.
TIP
The oil ring expander’s end gap cannot be
measured. If the oil ring rail’s gap is excessive,
replace all three oil rings.
Diameter D
76.955–76.970 mm (3.0297–
3.0303 in)
Measurement position H
9.0 mm (0.35 in)
Piston-to-cylinder clearance =
Cylinder bore - Piston diameter
Piston-to-cylinder clearance
0.030–0.055 mm (0.0012–0.0022
in)
Limit
0.15 mm (0.006 in)
b
a
Ring side clearance
0.030–0.065 mm (0.0012–0.0026
in)
Limit
0.120 mm (0.0047 in)
a. 10 mm (0.39 in)
Piston ring end gap
Top ring
End gap (installed)
0.15–0.25 mm (0.0059–0.0098 in)
Limit
0.50 mm (0.0197 in)
Oil ring
End gap (installed)
0.10–0.35 mm (0.0039–0.0138 in)
Summary of Contents for YZ 2015 Series
Page 6: ...EASB291006 YAMAHA MOTOR CORPORATION U S A YZ MOTORCYCLE LIMITED WARRANTY...
Page 10: ......
Page 33: ...CONTROL FUNCTIONS 1 21 a 2...
Page 65: ...LUBRICATION POINTS AND LUBRICANT TYPES 2 22 EASB291066...
Page 68: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 25...
Page 70: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 27...
Page 72: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 29...
Page 74: ...CABLE ROUTING DIAGRAM 2 31 EASB291068 CABLE ROUTING DIAGRAM...
Page 76: ...CABLE ROUTING DIAGRAM 2 33...
Page 78: ...CABLE ROUTING DIAGRAM 2 35...
Page 80: ...CABLE ROUTING DIAGRAM 2 37...
Page 82: ...CABLE ROUTING DIAGRAM 2 39...
Page 84: ...CABLE ROUTING DIAGRAM 2 41...
Page 86: ...CABLE ROUTING DIAGRAM 2 43...
Page 88: ...CABLE ROUTING DIAGRAM 2 45...
Page 128: ...ELECTRICAL SYSTEM 3 38...
Page 200: ...CHAIN DRIVE 4 70...
Page 244: ...ELECTRIC STARTER 5 41...
Page 266: ...OIL PUMP AND BALANCER GEAR 5 63 c d 6 6 7 8 8 b...
Page 286: ...TRANSMISSION 5 83...
Page 306: ...CHECKING THE INTAKE AIR TEMPERATURE SENSOR 8 67 CHECKING THE FUEL INJECTOR 8 68...
Page 321: ...CHARGING SYSTEM 8 15 EASB291338...
Page 325: ...COOLING SYSTEM For JPN 8 19 EASB291341...
Page 355: ...FUEL PUMP SYSTEM 8 49 EASB291348...
Page 356: ...ELECTRICAL COMPONENTS 8 50 ELECTRICAL COMPONENTS EASB291349 8 9 10 1 3 2 4 5 6 7...
Page 358: ...ELECTRICAL COMPONENTS 8 52 11 10 9 2 3 1 6 7 8 4 5...
Page 360: ...ELECTRICAL COMPONENTS 8 54 EASB291350 CHECKING THE SWITCHES 4 1 3 2 E B S E B E B E E B B...
Page 382: ...LIST OF SELF DIAGNOSTIC AND FAIL SAFE ACTIONS 9 7...