Page 328 of 364

–+ELEC
6 - 8 INSPECTION STEPS
If the starter motor will not operate, 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.
*3 marked: Refer to “MAIN SWITCH INSPECTION” section.
NOTE:
Remove the following parts before inspection.
1) Seat
2) Rear fender
3) Fuel tank
Use 12 V battery in this inspection.
Use the following special tools in this inspection.
Pocket tester:
YU-3112-C/90890-03112
*1 Check fuseReplace fuse and 
check wire harness.
*2 Check battery Recharge or replace.
Check each coupler and 
wire connection.Repair or replace.
*3 Check main switch. Replace.
Check starter motor 
operation.Repair or replace.
Check starting circuit 
cut-off relay.Replace.
Check starter relay. Replace.
Check neutral switch. Replace.
Check start switch. Replace.
OK
OK
OK
OK
OK
OK
OK
OK
No good
No good
No good
No good
No good
No good
No good
No good
No good
ELECTRIC STARTING SYSTEM (TT-R90E) 
     
        
        Page 344 of 364
–+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 
     
        
        Page 348 of 364
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