2005 YAMAHA TTR90 oil

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:
16.6 mm (0.65 in)
Mica undercut:
1.35 mm (0.05 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
0.018 ~ 0.022 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 (TT-R90E)

6 - 14
–+ELEC
5. Measure:
Brush length a
Out of specification → Replace.
Brush length wear limit:
3.5 mm (0.14 in)
6. Measure:
Brush spring force
Fatigue/out of specification → Replace
as a set.
Brush spring force:
3.92 ~ 5.88 N
(400 ~ 600 g, 14.1 ~ 21.2 oz)
ASSEMBLY
1. Install:
Brush holder
2. Install:
Armature coil 1
3. Install:
Ring 1
Stator assembly 2
Front bracket 3
NOTE:
Apply molybdenum grease lightly on to the
bearings of the starter motor.
Align the match mark on the yoke with the
match mark on the bracket.
ELECTRIC STARTING SYSTEM (TT-R90E)

–+ELEC
6 - 15
CHARGING SYSTEM (TT-R90E)
EC680000
CHARGING SYSTEM (TT-R90E)
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. Lighting coil Replace.
Replace rectifier/regulator.
OK
OK
OK
No good
OK
No good
No good
No good
No good
OK

6 - 16
–+ELECCHARGING SYSTEM (TT-R90E)
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
WB
R
Y/R
12
3. Inspect:
Lighting coil resistance
Out of specification → Replace.
Tester (+) lead → White lead 1
Tester (–) lead → Black lead 2
Lighting coil
resistanceTester selector
position
0.64 ~ 0.96 Ω at
20 ˚C (68 ˚F)Ω × 1
WSb
YB
1
2

–+ELEC
6 - 17
CARBURETOR HEATING SYSTEM
CARBURETOR HEATING SYSTEM
INSPECTION STEPS
Use the following steps for checking the possibility of the malfunctioning carburetor heating system.
NOTE:
Remove the following parts before inspection.
1) Seat
2) Fuel tank
Use the following special tools in this inspection.
Check entire carburetor
heating system for connec-
tion.Repair or replace.
Check thermo switch. Replace.
Check carburetor heater. Replace.
Check CDI magneto. Lighting coil Replace.
Replace rectifier/regulator.
Pocket tester:
YU-3112-C/90890-03112
OK
OK
OK
No good
No good
No good
No good
OK

6 - 20
–+ELECCARBURETOR HEATING SYSTEM
CARBURETOR HEATER INSPECTION
1. Inspect:
Carburetor heater resistance
Out of specification → Replace.
Tester (+) probe →
Carburetor heater terminal 1
Tester (–) probe →
Carburetor heater body 2
Carburetor
heater resistanceTester selector
position
6 ~ 10 Ω at
20 ˚C (68 ˚F)Ω × 1
CDI MAGNETO INSPECTION
1. Inspect:
Lighting coil resistance
Out of specification → Replace.
ÅTT-R90
ıTT-R90E
Tester (+) lead → Yellow lead 1
Tester (–) lead → Black lead 2
Lighting coil
resistanceTester selector
position
TT-R90:
0.28 ~ 0.42 Ω at
20 ˚C (68 ˚F)
TT-R90E:
0.52 ~ 0.78 Ω at
20 ˚C (68 ˚F)Ω × 1
W
Y
B
WSb
YB
1
2
1
2
Å
ı