Yamaha 2009 YFM25RY Service Manual page 26

Piston
Piston-to-cylinder clearance
Limit
Diameter D
Height H
Offset
Offset direction
Piston pin bore inside diameter
Limit
Piston pin outside diameter
Limit
Piston-pin-to-piston-pin-bore clearance
Limit
Piston ring
Top ring
Ring type
Dimensions (B × T)
End gap (installed)
Limit
Ring side clearance
Limit
2nd ring
Ring type
Dimensions (B × T)
End gap (installed)
Limit
Ring side clearance
Limit
Oil ring
Dimensions (B × T)
End gap (installed)
ENGINE SPECIFICATIONS
0.010–0.025 mm (0.0004–0.0010 in)
0.15 mm (0.0059 in)
73.983–73.998 mm (2.9127–2.9133 in)
5.0 mm (0.20 in)
0.25 mm (0.0098 in)
Intake side
17.002–17.013 mm (0.6694–0.6698 in)
17.043 mm (0.6710 in)
16.991–17.000 mm (0.6689–0.6693 in)
16.971 mm (0.6681 in)
0.002–0.022 mm (0.0001–0.0009 in)
0.072 mm (0.0028 in)
Barrel
0.90 × 2.75 mm (0.04 × 0.11 in)
0.19–0.31 mm (0.007–0.012 in)
0.56 mm (0.022 in)
0.030–0.065 mm (0.0012–0.0026 in)
0.115 mm (0.0045 in)
Taper
0.80 × 2.80 mm (0.03 × 0.11 in)
0.30–0.45 mm (0.012–0.018 in)
0.80 mm (0.032 in)
0.020–0.055 mm (0.0008–0.0022 in)
0.115 mm (0.0045 in)
1.50 × 2.60 mm (0.06 × 0.10 in)
0.10–0.35 mm (0.004–0.014 in)
2-7