Yamaha XG250, Service Manual

Page: 189 / 278

ELECTRIC STARTER
5-47
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.
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.
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.
6. Measure:
●
Brush spring force
Out of specification
→
Replace the brush
Limit
21.0 mm (0.83 in)
Mica undercut (depth)
1.50 mm (0.06 in)
a
a
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 M
Ω
at 20
°
C (68
°
F)
Limit
3.50 mm (0.14 in)
1
1
2
2
a