Yamaha YZF-R125, Service Manual

Page: 211 / 356

ELECTRIC STARTER
5-36
EAS24790
CHECKING THE STARTER MOTOR
1. Check:
• Commutator
Dirt
→
Clean with 600 grit sandpaper.
2. Measure:
• Commutator diameter “a”
Out of specification
→
Replace the starter
motor.
3. Measure:
• Mica undercut “a”
Out of specification
→
Scrape the mica to the
proper measurement with a hacksaw blade
that has been grounded to fit the commutator.
NOTE:
The mica of the commutator must be undercut to
ensure proper operation of the commutator.
4. Measure:
• Armature assembly resistances (commutator
and insulation)
Out of specification
→
Replace the starter
motor.
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a. Measure the armature assembly resistances
with the pocket tester.
b. If any resistance is out of specification, re-
place the starter motor.
▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲▲▲
5. Measure:
• Brush length “a”
Out of specification
→
Replace the starter
motor front cover/brush holder set.
6. Measure:
• Brush spring force
Out of specification
→
Replace the brush
springs as a set.
Limit
16.6 mm (0.65 in)
Mica undercut (depth)
1.35 mm (0.05 in)
a
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Armature coil
Commutator resistance “1”
0.0315–0.0385
Ω
Insulation resistance “2”
Above 1 M
Ω
Limit
3.50 mm (0.14 in)
Brush spring force
3.92–5.88 N (14.11–21.17 oz)
(400–600 gf)
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