Yamaha WR250F(S) Owner's Service Manual page 86

Piston pin bore inside diameter
Piston pin outside diameter
Piston rings:
Top ring:
Type
Dimensions (B × T)
End gap (installed)
Side clearance (installed)
2nd ring:
Type
Dimensions (B × T)
End gap (installed)
Side clearance
Oil ring:
Dimensions (B × T)
End gap (installed)
Crankshaft:
Crank width "A"
Runout limit "C"
Big end side clearance "D"
Small end free play "F"
MAINTENANCE SPECIFICATIONS
Item
T
T
B
T
Standard
16.002 ~ 16.013 mm
(0.6300 ~ 0.6304 in)
15.991 ~ 16.000 mm
(0.6296 ~ 0.6299 in)
B
Barrel
0.90 × 2.75 mm (0.04 × 0.11 in)
0.15 ~ 0.25 mm
(0.006 ~ 0.010 in)
0.030 ~ 0.065 mm
(0.0012 ~ 0.0026 in)
B
Taper
0.80 × 2.75 mm (0.03 × 0.11 in)
0.30 ~ 0.45 mm
(0.012 ~ 0.018 in)
0.020 ~ 0.055 mm
(0.0008 ~ 0.0022 in)
1.50 × 2.25 mm (0.06 × 0.09 in)
0.10 ~ 0.40 mm
(0.004 ~ 0.016 in)
55.95 ~ 56.00 mm
(2.203 ~ 2.205 in)
0.03 mm (0.0012 in)
0.15 ~ 0.45 mm
(0.0059 ~ 0.0177 in)
0.4 ~ 1.0 mm (0.02 ~ 0.04 in)
2 - 7
SPEC
Limit
16.043 mm
(0.6316 in)
15.971 mm
(0.6288 in)
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----
0.50 mm
(0.020 in)
0.12 mm
(0.005 in)
----
----
0.80 mm
(0.031 in)
0.12 mm
(0.005 in)
----
----
----
0.05 mm
(0.002 in)
0.50 mm
(0.02 in)
2.0 mm
(0.08 in)