Yamaha TT-R50E Owner's Service Manual page 366

ELECTRIC STARTING SYSTEM
INSPECTION AND REPAIR
1. Inspect:
2. Measure:
3. Measure:
NOTE:
The mica insulation of the commutator must be
undercut to ensure proper operation of com-
mutator.
4. Measure:
Measurement steps:
• Measure the armature assembly resis-
• If any resistance is out of specification,
6 - 12
• Commutator
Dirt → Clean it with #600 grit sandpaper.
• Commutator diameter a
Commutator wear limit:
16.6 mm (0.65 in)
Out of specification → Replace the
starter motor.
• Mica undercut a
Mica undercut:
1.35 mm (0.05 in)
Out of specification → Scrape the mica to
the proper value (a hacksaw blade can
be ground to fit).
• Armature assembly resistance (commu-
tator and insulation)
Out of specification → Replace the
starter motor.
tances with the pocket tester.
Pocket tester:
YU-03112-C/90890-03112
Armature coil:
Commutator resistance 1
0.035 ~ 0.043 Ω at 20 °C (68 °F)
Insulation resistance 2
Above 1 MΩ at 20 °C (68 °F)
replace the starter motor.
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ELEC