Yamaha WR450F(R) Owner's Service Manual page 660

INSPECTION STEPS
If the starter motor will not operate, use the following inspection steps.
*1 Check fuse
*2 Check battery
Check each coupler and
wire connection.
*3 Check main switch.
Check starter motor
operation.
Check starting circuit
cut-off relay.
Check starter relay.
*4 Check neutral switch.
Check clutch switch.
Check diode.
Check start switch.
*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.
*4 marked: Refer to "NEUTRAL SWITCH INSPECTION" section.
NOTE:
Remove the following parts before inspection.
G
1) Seat
2) Rear fender
Use 12 V battery in this inspection.
G
Use the following special tools in this inspection.
G
Pocket tester:
YU-3112-C/90890-03112
ELECTRIC STARTING SYSTEM
OK
OK
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
No good
No good
6 - 8
– +
ELEC
Replace fuse and
check wire harness.
Recharge or replace.
Repair or replace.
Replace.
Repair or replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.