Yamaha WR250F(R), Owner'S Service Manual

Page: 86 / 860

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