Yamaha XG250 Service Manual page 22

Piston
Piston-to-cylinder clearance
Limit
Diameter D
Height H
D
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)
T
End gap (installed)
Limit
Ring side clearance
Limit
2nd ring
Ring type
Dimensions (B × T)
T
End gap (installed)
Limit
Ring side clearance
Limit
Oil ring
Dimensions (B × T)
T
End gap (installed)
0.025–0.050 mm (0.0010–0.0020 in)
0.15 mm (0.0059 in)
73.960–73.975 mm (2.9118–2.9124 in)
11.0 mm (0.43 in)
H
0.50 mm (0.0197 in)
Intake side
16.002–16.013 mm (0.6300–0.6304 in)
16.043 mm (0.6316 in)
15.991–16.000 mm (0.6296–0.6299 in)
15.970 mm (0.6287 in)
0.002–0.022 mm (0.0001–0.0009 in)
0.073 mm (0.0029 in)
Barrel
0.90 × 2.75 mm (0.04 × 0.11 in)
B
0.19–0.31 mm (0.0075–0.0122 in)
0.60 mm (0.0236 in)
0.030–0.065 mm (0.0012–0.0026 in)
0.100 mm (0.0039 in)
Taper
0.80 × 2.80 mm (0.03 × 0.11 in)
B
0.30–0.45 mm (0.0118–0.0177 in)
0.60 mm (0.0236 in)
0.020–0.055 mm (0.0008–0.0022 in)
0.100 mm (0.0039 in)
1.50 × 2.60 mm (0.06 × 0.10 in)
B
0.10–0.35 mm (0.0039–0.0138 in)
2-6
ENGINE SPECIFICATIONS