2016 YAMAHA YZ450F diagram

IGNITION SYSTEM
8-5
The launch control indicator light fail to blink.
TIP
Before troubleshooting, remove the following part(s):
1. Seat
2. Air scoop (left)8. Check the ignition system wire har-
ness.
Refer to “CIRCUIT DIAGRAM” on
page 8-2.NG 
Repair or replace the wire harness.
OK 
Replace the ECU.
1. Check the launch control switch
coupler connections.NG 
Reconnect.
OK 
2. Check the neutral switch coupler
connections.NG 
Reconnect.
OK 
3. Check the launch control switch.
Refer to “CHECKING THE
SWITCHES” on page 8-38.NG 
Replace the launch control switch.
OK 
4. Check the neutral switch.
Refer to “CHECKING THE NEU-
TRAL SWITCH” on page 8-46.NG 
Replace the neutral switch.
OK 
5. Check the fuel ignition system wire
harness.
Refer to “CIRCUIT DIAGRAM” on
page 8-2.NG 
Repair or replace the wire harness.
OK 
Replace the ECU.

CHARGING SYSTEM
8-6
EAS27200
CHARGING SYSTEM
EASB111322CIRCUIT DIAGRAM
ONOFF
ONOFF
B R
RRRRRRRR
BBBBBB
LLL
B/LB/LB/LB/LB/LB/L
B/L
Gy
W
W
W
W
R
R
B
B
B
B
RY/RY/G
Y/GY/B
Y/B
Y/W
Y/WB/YL/WB/R
B/Y
B/Y
B/W
R/B
R/B
B/R
B/R
G/WP/B
P/B
B/L
B/L
B/L
G/W
Br/W
Br/W
B/LB/L
B/W
Y/RSbP
Sb
Sb
P
P
P
L
L
LY
Y
B
B
LgGy
Lg
R
R
R
R
R
R
O
O
O
RO
WWW W
W W
W W
R B
B/LGyB Gy
BRRB
RLgB/W
B/YB
B B
PP/LSbSbY/WP
B RY/R Y/GBB/WWR/Y
BGy R
B/WB/LLYP/BG/WB/R
R/BLg
Br/W
P
O
Y/GB/YP/LY/RSb
RR/B
RB/R
B/LBr/WB/L G/W
LYB/L
B/LP/BL
L LLRRRRRRRR
BBBBBB
B/L B/L B/L B/L B/L B/L
R O
OR

CHARGING SYSTEM
8-8
EASB111323TROUBLESHOOTING
The condenser is not being charged.
TIP
Before troubleshooting, remove the following part (s):
1. Seat
2. Air scoop (left)
1. Check the entire charging system’s
wiring.NG 
Reconnect.
OK 
2. Check the rectifier/regulator.
Refer to “CHECKING THE RECTI-
FIER/REGULATOR” on page 8-43.NG 
Replace the rectifier/regulator.
OK 
3. Check the stator coil.
Refer to “CHECKING THE STA-
TOR COIL” on page 8-42.NG 
Replace the stator coil.
OK 
4. Check the charging system wire
harness.
Refer to “CIRCUIT DIAGRAM” on
page 8-6.NG 
Repair or replace the wire harness.
OK 
Replace the condenser.

FUEL INJECTION SYSTEM
8-10
EASB111324
FUEL INJECTION SYSTEM
EASB111325CIRCUIT DIAGRAM
ONOFF
ONOFF
B R
RRRRRRRR
BBBBBB
LLL
B/LB/LB/LB/LB/LB/L
B/L
Gy
W
W
W
W
R
R
B
B
B
B
RY/RY/G
Y/GY/B
Y/B
Y/W
Y/WB/YL/WB/R
B/Y
B/Y
B/W
R/B
R/B
B/R
B/R
G/WP/B
P/B
B/L
B/L
B/L
G/W
Br/W
Br/W
B/LB/L
B/W
Y/RSbP
Sb
Sb
P
P
P
L
L
LY
Y
B
B
LgGy
Lg
R
R
R
R
R
R
O
O
O
RO
WWW W
W W
W W
R B
B/LGyB Gy
BRRB
RLgB/W
B/YB
B B
PP/LSbSbY/WP
B RY/R Y/GBB/WWR/Y
BGy R
B/WB/LLYP/BG/WB/R
R/BLg
Br/W
P
O
Y/GB/YP/LY/RSb
RR/B
RB/R
B/LBr/WB/L G/W
LYB/L
B/LP/BL
L LLRRRRRRRR
BBBBBB
B/L B/L B/L B/L B/L B/L
R O
OR

FUEL PUMP SYSTEM
8-32
EASB111328
FUEL PUMP SYSTEM
EASB111329CIRCUIT DIAGRAM
ONOFF
ONOFF
B R
RRRRRRRR
BBBBBB
LLL
B/LB/LB/LB/LB/LB/L
B/L
Gy
W
W
W
W
R
R
B
B
B
B
RY/RY/G
Y/GY/B
Y/B
Y/W
Y/WB/YL/WB/R
B/Y
B/Y
B/W
R/B
R/B
B/R
B/R
G/WP/B
P/B
B/L
B/L
B/L
G/W
Br/W
Br/W
B/LB/L
B/W
Y/RSbP
Sb
Sb
P
P
P
L
L
LY
Y
B
B
LgGy
Lg
R
R
R
R
R
R
O
O
O
RO
WWW W
W W
W W
R B
B/LGyB Gy
BRRB
RLgB/W
B/YB
B B
PP/LSbSbY/WP
B RY/R Y/GBB/WWR/Y
BGy R
B/WB/LLYP/BG/WB/R
R/BLg
Br/W
P
O
Y/GB/YP/LY/RSb
RR/B
RB/R
B/LBr/WB/L G/W
LYB/L
B/LP/BL
L LLRRRRRRRR
BBBBBB
B/L B/L B/L B/L B/L B/L
R O
OR

FUEL PUMP SYSTEM
8-34
EASB111330TROUBLESHOOTING
The fuel pump fails to operate.
TIP
Before troubleshooting, remove the following part(s):
1. Seat
2. Side cover (left/right)
3. Air scoop (left/right)
4. Fuel tank
5. Air filter case cover
1. Check the fuel pump system wire
harness connections.NG 
Reconnect.
OK 
2. Check the engine stop switch.
Refer to “CHECKING THE
SWITCHES” on page 8-38.NG 
Replace the engine stop switch.
OK 
3. Check fuel pressure.
Refer to “CHECKING THE FUEL
PRESSURE” on page 7-3.NG 
Replace the fuel pump.
OK 
4. Check the fuel pump system wire
harness.
Refer to “CIRCUIT DIAGRAM” on
page 8-32.NG 
Repair or replace the wire harness.
OK 
Replace the ECU.

ELECTRICAL COMPONENTS
8-40
Check each switch for continuity with the pocket tester. If the continuity reading is incorrect, check
the wiring connections and if necessary, replace the switch.
ECA14370
NOTICE
Never insert the tester probes into the coupler terminal slots “1”. Always insert the probes
from the opposite end of the coupler, taking care not to loosen or damage the leads.
TIP
• Before checking for continuity, set the pocket tester range to “ 1” to make a “0” adjustment.
• When checking for continuity, switch back and forth between the switch positions a few times.
Terminal connections of the switch are shown in the terminal connection diagram below.
The switch positions “a” are shown in the far left column and the switch lead colors are shown in the
top row in the switch illustration.
TIP
“ ” indicates continuity between switch terminals (i.e., a closed circuit at each switch posi-
tion).
The example illustration below shows that:
There is continuity between red and brown when the switch is “ON”.Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
a

EASB111381
WIRING DIAGRAM
YZ450F/YZ450FG 2016
1. Crankshaft position sensor
2. AC magneto
3. Rectifier/regulator
4. Joint connector
5. Condenser
6. Coupler for connecting option-
al part
7. Engine stop switch
8. Neutral switch
9. Launch control switch
10. ECU
11. Ignition coil
12. Spark plug
13. Fuel injector
14. Fuel pump
15. Intake air temperature sensor
16. Coolant temperature sensor
17. Throttle position sensor
18. Intake air pressure sensor
19. Ignition coil sub-lead
EASB111382COLOR CODE
BBlack
Gy Gray
LBlue
Lg Light green
O Orange
PPink
RRed
Sb Sky blue
Y Yellow
B/L Black/Blue
B/R Black/Red
B/W Black/White
B/Y Black/Yellow
Br/W Brown/White
G/W Green/White
L/W Blue/White
P/B Pink/Black
R/B Red/Black
Y/G Yellow/Green
Y/R Yellow/Red
Y/W Yellow/White