Yamaha TT-R125EY, Service Manual

Page: 252 / 258

6-13
ELEC
– +
ELECTRIC STARTING SYSTEM
Out of specification
→
Replace the starter
motor.
3. Measure:
• Mica undercut
a
INSPECTION AND REPAIR
1. Inspect:
• Commutator
Dirt
→
Clean it with #600 grit sandpaper.
2. Measure:
• Commutator diameter
a
Commutator wear limit:
21.0 mm (0.83 in)
Out of specification
→
Scrape the mica
to the proper value (a hacksaw blade can
be ground to fit).
The mica insulation of the commutator must be
undercut to ensure proper operation of
commutator.
Mica undercut:
1.5 mm (0.06 in)
4. Measure:
• Armature assembly resistance (commuta-
tor and insulation)
Out of specification
→
Replace the starter
motor.
Pocket tester:
YU-3112-C/90890-03112
Measurement steps:
• Measure the armature assembly resis-
tances with the pocket tester.
Armature coil:
Commutator resistance
1
0.017 ~ 0.021
Ω
at 20 °C (68 °F)
Insulation resistance
2
Above 1 M
Ω
at 20 °C (68 °F)
• If any resistance is out of specification,
replace the starter motor.
TIP