Yamaha MT-09 2021 - Assembling the Starter Motor; Checking the Starter Motor

5-43
ELECTRIC STARTER
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.
TIP
The mica of the commutator must be undercut to
ensure proper operation of the commutator.
3. Check:
• Armature assembly
a. Connect the digital circuit tester and check
the continuity.
b. If there is no continuity, replace the starter
motor.
4. Measure:
• Brush length “a”
Out of specification → Replace the brush
holder set.
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.
Mica undercut (depth)
0.70 mm (0.03 in)
Digital circuit tester (CD732)
90890-03243
Model 88 Multimeter with ta-
chometer
YU-A1927
G088986
Brush overall length limit
6.5 mm (0.26 in)
G088989
1