Yamaha 2002 YFA1 - Page 12

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SPEC
MAINTENANCE SPECIFICATIONS
Inside diameter (valve guide)
Intake 5.000 ~ 5.012 mm (0.197 in)
Exhaust 5.000 ~ 5.012 mm (0.197 in)
Stem-to-guide clearance
Intake 0.010 ~ 0.037 mm (0.004 ~ 0.0014 in)
Exhaust 0.025 ~ 0.052 mm (0.0010 ~ 0.0020 in)
Stem runout limit 0.01 mm (0.0004 in)
Valve seat width
Intake 0.9 ~ 1.1 mm (0.035 ~ 0.043 in)
Exhaust 0.9 ~ 1.1 mm (0.035 ~ 0.043 in)
Piston:
Piston size “D” 48.96 ~ 49.00 mm (1.927 ~ 1.929 in)
Measuring point “H” 6 mm (0.24 in)
From bottom of the piston.
Piston-to-cylinder clearance 0.020 ~ 0.040 mm (0.0008 ~ 0.0016 in)
<Wear limit> <0.15 mm (0.006 in)>
Over size 2nd 49.5 mm (1.95 in)
4th 50.0 mm (1.97 in)
Piston off-set 0.5 mm (0.02 in)
Piston off-set direction Intake side
Inside diameter (piston pin bore) 13.002 ~ 13.013 mm (0.5119 ~ 0.5123 in)
Outside diameter (piston pin) 12.996 ~ 13.000 mm (0.5117 ~ 0.5118 in)
Piston pin-to-piston clearance 0.002 ~ 0.017 mm (0.0001 ~ 0.0006 in)
<Limit> <0.07 mm (0.003 in)>
Piston ring:
Ty p e
Top ring Barrel
2nd ring Taper
Dimension (B × T)
Top ring 1.0 × 2.0 mm (0.039 × 0.079 in)
Second ring 1.0 × 2.0 mm (0.039 × 0.079 in)
Oil ring 2.0 × 2.2 mm (0.079 × 0.087 in)
End gap (installed)
Top ring 0.15 ~ 0.30 mm (0.006 ~ 0.012 in)
Second ring 0.15 ~ 0.30 mm (0.006 ~ 0.012 in)
Oil ring 0.20 ~ 0.80 mm (0.008 ~ 0.031 in)
Model YFA1 (P) 2002
H
D
T
B
B
T
B
T