Yamaha YXR70FX Service Manual page 452

STARTER MOTOR
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a. Measure the armature assembly resis-
tances with the pocket tester.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Armature coil
Commutator resistance 1
0.0250 ~ 0.0350 Ω at
20 °C (68 °F)
Insulation resistance 2
Above 1 MΩ at 20 °C (68 °F)
b. If any resistance is out of specification,
replace the starter motor.
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5. Measure:
• brush length a
Out of specification → Replace the brushes
as a set.
Brush length wear limit
5.00 mm (0.20 in)
6. Measure:
• brush spring force
Out of specification → Replace the brush
springs as a set.
Brush spring force
7.65 ~ 10.01 N (780 ~ 1021 gf,
27.54 ~ 36.03 oz)
7. Check:
• gear teeth
Damage/wear → Replace the gear.
8. Check:
• bearing
• oil seal
Damage/wear → Replace the defective
part(s).
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