Checking The Starter Motor - Yamaha YZF-R1B 2012 Service Manual

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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.
Limit
23.5 mm (0.93 in)
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.
Mica undercut (depth)
1.50 mm (0.06 in)
TIP
The mica of the commutator must be undercut
to ensure proper operation of the commutator.
4. Measure:
• Armature assembly resistances (commu-
tator and insulation)
Out of specification → Replace the
starter motor.
email: info@motomatrix.co.uk
ELECTRIC STARTER
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Measure the armature assembly resis-
tances with the digital circuit tester.
Digital circuit tester
90890-03174
Model 88 Multimeter with
tachometer
YU-A1927
Armature coil
Commutator resistance
0.0090–0.0110 Ω at 20 °C (68
°F)
Insulation resistance
Above 1 MΩ at 20 °C (68 °F)
b. If any resistance is out of specification,
replace the starter motor.
1. Commutator resistance
2. Insulation resistance
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
5. Measure:
• Brush length "a"
Out of specification → Replace the brush
holder.
Limit
7.19 mm (0.28 in)
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