Checking The Starter Motor; Assembling The Starter Motor - Yamaha MT-09 2021 Service Manual

EAS30325

CHECKING THE STARTER MOTOR

1. Check:
• Commutator
Dirt → Clean with 600 grit sandpaper.
2. 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)
0.70 mm (0.03 in)
TIP
The mica of the commutator must be undercut to
ensure proper operation of the commutator.
G088986
3. Check:
• Armature assembly
a. Connect the digital circuit tester and check
the continuity.
Digital circuit tester (CD732)
90890-03243
Model 88 Multimeter with ta-
chometer
YU-A1927
b. If there is no continuity, replace the starter
motor.
ELECTRIC STARTER
4. Measure:
• Brush length "a"
Out of specification → Replace the brush
holder set.
Brush overall length limit
6.5 mm (0.26 in)
G088989
5. Check:
• Gear teeth
Damage/wear → Replace the starter motor
assembly.
6. Check:
• Bearing
• Oil seal
Damage/wear → Replace the starter motor
assembly.
EAS30326

ASSEMBLING THE STARTER MOTOR

1. Install:
• Brush holder set
• Insulator "1"
TIP
Install the insulator as shown in the illustration.
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1