Yamaha FZR400 1988-1989 Service Manual page 378

YAMAHA EXHAUST VARIABLE VALVE SYSTEM
TROUBLESHOOTING
WHEN MAIN SWITCH IS TURNED TO "ON", EXUP SERVOMOTOR DOES
NOT OPERATE ONE CYCLE.
Procedure (1)
Check;
1. Voltage
2. EXUP servomotor operation
3. EXUP servomotor operation
4. Wiring connection
(Entire EXUP system)
NOTE:
Remove the following parts before troubleshooting.
??
1) Seat
2) Seat cowling
??
Use the following special tool in this troubleshooting.
Pocket Tester:
P/N. YU-03112
Procedure ( 1)
@Connect the pocket tester (DC20V) to the
"EXUP control unit " @ connector.
Tester (+) Lead -+ Red/White @ Terminal
Tester (-) Lead + Black @ Terminal
Procedure (2)
Check;
1. Fuse "MAIN/IGNITION"
2. Battery
3. Main switch
4. "ENGINE STOP" switch
5. Wiring connection
(Entire EXUP system)
3) Lower cowling (Left)