Checking The Starter Motor - Yamaha XG250 Service Manual

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
21.0 mm (0.83 in)
a
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 commuta-
tor.
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 coil assembly resistances (com-
●
mutator and insulation)
Out of specification → Replace the starter
motor.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
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 brushes
as a set.
a
a
6. Measure:
Brush spring force
●
Out of specification → Replace the brush
5-47
ELECTRIC STARTER
Digital circuit tester
90890-03174
Model 88 Multimeter with tachome-
ter
YU-A1927
Armature coil
Commutator resistance "1"
0.0126–0.0154 Ω at 20°C (68°F)
Insulation resistance "2"
Above 1 MΩ at 20°C (68°F)
2
1
2
1
Limit
3.50 mm (0.14 in)