Yamaha RX10K, Supplementary Service Manual

Page: 366 / 523

8-14
ELECTRICAL STARTING SYSTEM
ELEC
CAUTION:
Inspection
1. Inspect:
S
Commutator (outer surface)
Dirty
!
Clean with #600 grit sandpaper 1 .
Hold the armature in a vise 2 and copper or
aluminium plate 3 .
Lightly grip the armature with a vise.
2. Measure:
S
Commutator (diameter)
Measure the diameter
a
of the commutator
at points where the brush comes in contact.
Out of specification
!
Replace the starter
motor.
Commutator wear limit:
27.5 mm (1.08 in)
3. Measure:
S
Mica (insulation depth) 1
(between commutator segments)
Out of specification
!
Scrape mica to proper
limits
a
.
Use a hacksaw blade 2 that is ground to fit.
Mica undercut:
1.5 mm (0.059 in)
4. Measure:
S
Armature coil resistance
(insulation / continuity)
Defect(s)
!
Replace the starter motor.
Inspection steps:
S
Connect the pocket tester for the continuity
check
1 and the insulation check 2 .
S
Measure the armature coil resistances.
Armature coil resistance:
Continuity check:
0.008
X
0.010
Ω
at 20
_
C
(68
_
F)
Insulation check:
More than 100 k
Ω
at 20
_
C
(68
_
F)
S
If the resistance is incorrect, replace the start-
er motor.