2003 YAMAHA TTR125 oil

6 - 11
–+ELEC
STARTER MOTOR
7
4
3
52
1
5 8
0
90
95
6
1
New
New
New
Extent of removal:1 Starter motor disassembly
Extent of removal Order Part name Q’ty Remarks
STARTER MOTOR REMOVAL
Preparation for removal Drain the engine oil. Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
1 Starter motor 1
STARTER MOTOR DISASSEM-
BLY
1Starter motor front cover 1
2Washer (starter motor front
cover)1
3Plain washer 1
4Circlip 1
5O-ring
3
1
ELECTRIC STARTING SYSTEM

6 - 13
–+ELEC
INSPECTION AND REPAIR
1. Inspect:
Commutator
Dirt → Clean it 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 value (a hacksaw blade
can be ground to fit).
NOTE:
The mica insulation of the commutator must be
undercut to ensure proper operation of com-
mutator.
Commutator wear limit:
21.0 mm (0.83 in)
Mica undercut:
1.5 mm (0.06 in)
4. Measure:
Armature assembly resistance (com-
mutator and insulation)
Out of specification → Replace the
starter motor.
Measurement steps:
Measure the armature assembly resis-
tances with the pocket tester.
Pocket tester
YU-3112-C/90890-03112
Armature coil:
Commutator resistance 1
0.017 ~ 0.021 Ω at 20 ˚C (68 ˚F)
Insulation resistance 2
Above 1 MΩ at 20 ˚C (68 ˚F)
If any resistance is out of specification,
replace the starter motor.
ELECTRIC STARTING SYSTEM

–+ELEC
6 - 16
CHARGING SYSTEM
EC680000
CHARGING SYSTEM
EC681001
INSPECTION STEPS
If the battery is not charged, use the following inspection steps.
*1 marked: Refer to “FUSE INSPECTION” section in the CHAPTER 3.
*2 marked: Refer to “BATTERY INSPECTION AND CHARGING” section in the CHAPTER 3.
NOTE:
Remove the following parts before inspection.
1) Seat
2) Rear fender
3) Fuel tank
Use the following special tool in this inspection.
Pocket tester:
YU-3112-C/90890-03112Inductive tachometer:
YU-8036-B
Engine tachometer:
90890-03113
*1 Check fuse.Replace fuse and
check wire harness.
*2 Check battery. Recharge or replace.
Check each coupler and
wire connection.Repair or replace.
Check charging voltage.Charging system is
good.
Check CDI magneto. Charging coil Replace.
Replace rectifier/regulator.
OK
OK
OK
No good
OK
No good
No good
No good
No good
OK

6 - 17
–+ELECCHARGING SYSTEM
EC624000
COUPLERS AND LEADS CONNECTION
INSPECTION
1. Check:
Couplers and leads connection
Rust/dust/looseness/short-circuit →
Repair or replace.
CHARGING VOLTAGE INSPECTION
1. Start the engine.
2. Inspect:
Charging voltage
Out of specification → If no failure is
found in checking the source coil resis-
tance, replace the rectifier/regulator.
Tester (+) lead → Red lead 1
Tester (–) lead → Black lead 2
Charging
voltageTester selector
position
14.0 ~ 15.0 V at
5,000 r/minDCV-20
W
B
RY
2
1
3. Inspect:
Charging coil resistance
Out of specification → Replace.
Tester (+) lead → White lead 1
Tester (–) lead → Black lead 2
Charging coil
resistanceTester selector
position
0.64 ~ 0.96 Ω at
20 ˚C (68 ˚F)Ω × 1
WSb
YB
1
2