CYLINDER AND PISTON
5-27
EAS24440
CHECKING THE PISTON PIN
1. Check:
• Piston pin
Blue discoloration/grooves
→
Replace
the piston pin and then check the lubrica-
tion system.
2. Measure:
• Piston pin outside diameter “a”
Out of specification
→
Replace the piston
pin.
3. Measure:
• Piston pin bore diameter “b”
Out of specification
→
Replace the pis-
ton.
4. Calculate:
• Piston-pin-to-piston-pin-bore clearance
Out of specification
→
Replace the piston
pin and piston as a set.
EAS24450
INSTALLING THE PISTON AND CYLINDER
1. Install:
• Lower oil ring rail “1”
• Oil ring expander “2”
Piston ring
Top ring
End gap (installed)
0.19–0.31 mm (0.007–0.012 in)
Limit
0.56 mm (0.022 in)
2nd ring
End gap (installed)
0.30–0.45 mm (0.012–0.018 in)
Limit
0.80 mm (0.032 in)
Oil ring
End gap (installed)
0.10–0.35 mm (0.004–0.014 in)
a. 40 mm (1.476 in)
Piston pin outside diameter
16.991–17.000 mm (0.6689–
0.6693 in)
Limit
16.971 mm (0.6681 in)
Piston pin bore inside diameter
17.002–17.013 mm (0.6694–
0.6698 in)
Limit
17.043 mm (0.6710 in)
• Piston-pin-to-piston-pin-bore clearance =
Piston pin bore diameter “b” -
Piston pin outside diameter “a”
Piston-pin-to-piston-pin-bore
clearance
0.002–0.022 mm (0.0001–
0.0009 in)
Limit
0.072 mm (0.0028 in)
Summary of Contents for 2009 YFM25RY
Page 1: ...SERVICE MANUAL YFM25RY YFM25RSEY YFM25RSE2Y 4D3 28197 11 LIT 11616 22 09 2009 ...
Page 8: ......
Page 39: ...LUBRICATION POINTS AND LUBRICANT TYPES 2 20 ...
Page 42: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 23 EAS20410 LUBRICATION DIAGRAMS ...
Page 44: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 25 ...
Page 46: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 27 ...
Page 47: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 28 1 Oil cooler 2 Oil hose 1 3 Oil hose 2 ...
Page 48: ...CABLE ROUTING 2 29 EAS20430 CABLE ROUTING ...
Page 50: ...CABLE ROUTING 2 31 ...
Page 52: ...CABLE ROUTING 2 33 ...
Page 54: ...CABLE ROUTING 2 35 ...
Page 56: ...CABLE ROUTING 2 37 ...
Page 58: ...CABLE ROUTING 2 39 ...
Page 60: ...CABLE ROUTING 2 41 ...
Page 62: ...CABLE ROUTING 2 43 ...
Page 65: ......
Page 143: ...HANDLEBAR 4 42 Throttle cable free play 2 0 4 0 mm 0 08 0 16 in ...
Page 162: ...CHAIN DRIVE 4 61 ...
Page 165: ......
Page 240: ...CARBURETOR 6 9 ...
Page 242: ...IGNITION SYSTEM 7 1 EAS27090 IGNITION SYSTEM EAS27100 CIRCUIT DIAGRAM ...
Page 246: ...ELECTRIC STARTING SYSTEM 7 5 EAS27160 ELECTRIC STARTING SYSTEM EAS27170 CIRCUIT DIAGRAM ...
Page 252: ...CHARGING SYSTEM 7 11 EAS27200 CHARGING SYSTEM EAS27210 CIRCUIT DIAGRAM ...
Page 255: ...CHARGING SYSTEM 7 14 ...
Page 256: ...LIGHTING SYSTEM 7 15 EAS27240 LIGHTING SYSTEM EAS27250 CIRCUIT DIAGRAM ...
Page 260: ...SIGNALING SYSTEM 7 19 EAS27270 SIGNALING SYSTEM EAS27280 CIRCUIT DIAGRAM ...
Page 264: ...CARBURETOR HEATING SYSTEM 7 23 EAS27490 CARBURETOR HEATING SYSTEM EAS27500 CIRCUIT DIAGRAM ...
Page 267: ...CARBURETOR HEATING SYSTEM 7 26 ...
Page 268: ...ELECTRICAL COMPONENTS 7 27 EAS27972 ELECTRICAL COMPONENTS ...
Page 270: ...ELECTRICAL COMPONENTS 7 29 EAS27980 CHECKING THE SWITCHES ...
Page 284: ...ELECTRICAL COMPONENTS 7 43 ...
Page 291: ......
Page 292: ...YAMAHA MOTOR CO LTD 2500 SHINGAI IWATA SHIZUOKA JAPAN ...
Page 293: ...WIRING DIAGRAM YFM25RY YFM25RSEY YFM25RSE2Y ...