Checking The Starter Motor - Yamaha YZF-R1 2007 Service Manual

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EAS24790

CHECKING THE STARTER MOTOR

1. Check:
• Commutator
Dirt → Clean with 1000 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)
NOTE:
The mica of the commutator must be undercut
to ensure proper operation of the commutator.
4. Measure:
• Armature assembly resistances (commuta-
tor and insulation)
Out of specification → Replace the starter
motor.
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a. Measure the armature assembly resis-
tances with the pocket tester.
email: info@motomatrix.co.uk
ELECTRIC STARTER
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Armature coil
Commutator resistance "1"
0.009–0.011 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.
Limit
7.19 mm (0.28 in)
6. Measure:
• Brush spring force
Out of specification → Replace the brush
springs as a set.
Brush spring force
5.28–7.92 N (19.01–28.51 oz)
(538–808 gf)
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