2016 YAMAHA WR 450F relay

FUEL TANK
8-4
EAS2GC1344REMOVING THE FUEL SENDER
1. Remove:• Fuel sender
ECA
NOTICE
Do not drop the fuel sender or give it a
strong shock.
EAS2GC1345CHECKING THE FUEL SENDER
1. Disconnect:• Fuel pump coupler
• Fuel sender coupler
(from the wire harness)
2. Disconnect: • Starter motor lead
(from starter relay)
3. Remove: • Fuel tank
4. Remove: • Fuel sender(from the fuel tank)
5. Connect: • Fuel sender coupler
6. Push the start switch.
7. Check:
• Fuel level warning lightOut of specification  Replace the fuel
sender.
EAS2GC1346INSTALLING THE FUEL SENDER
1. Install: • Fuel sender gasket
• Fuel sender
TIP
• Do not damage the installation surfaces of the
fuel tank when installing the fuel sender.
• Always use a new fuel sender gasket.
• Install the fuel sender as shown in the illustra-
tion.
• When install the fuel sender, make sure that
the projection “a” faces the rear of the vehicle.
EAS2GC1347INSTALLING THE FUEL TANK
1. Install: • Fuel tank
2. Connect:
• Fuel hose
ECA
NOTICE
• Connect the fuel hose securely, and check that the orientation of the installed fuel
hose holder is correct.
• Take care not to kink or pinch the fuel
hose.
Fuel pump is atmosphere “A”
 Fuel level warning light is come on
Fuel pump is soaked in fuel “B”
 Fuel level warning light is goes off
a
b
4
1
2
6
5 3
Fuel sender bolts
4.0 Nm (0.40 m·kgf, 2.9 ft·lbf)
New
T R..
a

ELECTRICAL COMPONENTS....................................................................... 9-60
CHECKING THE SWITCHES .................................................................. 9-64
CHECKING THE BULBS AND BULB SOCKETS .................................... 9-67
CHECKING THE FUSES ......................................................................... 9-68
CHECKING AND CHARGING THE BATTERY ........................................ 9-69
CHECKING THE RELAYS ....................................................................... 9-72
CHECKING THE DIODE .......................................................................... 9-73
CHECKING THE IGNITION SPARK GAP................................................ 9-73
CHECKING THE SPARK PLUG CAP ...................................................... 9-73
CHECKING THE IGNITION COIL ............................................................ 9-74
CHECKING THE CRANKSHAFT POSITION SENSOR........................... 9-74
CHECKING THE LEAN ANGLE SENSOR............................................... 9-75
CHECKING THE STARTER MOTOR OPERATION ................................ 9-75
CHECKING THE STATOR COIL ............................................................. 9-76
CHECKING THE RECTIFIER/REGULATOR ........................................... 9-76
CHECKING THE SPEED SENS OR ......................................................... 9-77
CHECKING THE FUEL SENDER ............................................................ 9-77
CHECKING THE RESISTER ................................................................... 9-77
CHECKING THE RADIATOR FAN MOTOR ............................................ 9-78
CHECKING THE COOLANT TEMPERATURE SENSOR........................ 9-78
CHECKING THE THROTTLE POSITION SENSOR ................................ 9-79
CHECKING THE THROTTLE POSITION SENSOR INPUT VOLTAGE .. 9-79
CHECKING THE INTAKE AIR PR ESSURE SENSOR ............................ 9-80
CHECKING THE INTAKE AIR TEMPERATURE SENSOR ..................... 9-80
CHECKING THE FUEL INJECTOR ......................................................... 9-81

IGNITION SYSTEM
9-3
1. Joint connector
2. Joint connector
4. AC magneto
9. Battery
10.Frame ground
11.Starter relay
12.Main fuse
22.ECU (engine control unit)
23.Ignition coil
24.Spark plug
30.Joint connector
35.Lean angle sensor
36.Engine stop switch
48.Frame ground
49.Ignition coil sub-lead
50.Negative battery lead

ELECTRIC STARTING SYSTEM
9-7
1. Joint connector
2. Joint connector
3. Joint connector
7. Main relay
9. Battery
10.Frame ground
11.Starter relay
12.Main fuse
13.Starter motor
14.Starter relay diode
22.ECU (engine control unit)
30.Joint connector
36.Engine stop switch
37.Neutral switch
38.Diode
39.Starting circuit cut-off relay
40.Clutch switch
41.Start switch
48.Frame ground
50.Negative battery lead

ELECTRIC STARTING SYSTEM
9-8
EAS2GC1362STARTING CIRCUIT CUT-OFF SYSTEM OPERATION
If the meter light comes on, the starter motor can only operate if at least one of the following condi-
tions is met:
• The transmission is in neutral (the neutral switch is closed).
• The clutch lever is pulled to the handlebar (the clutch switch is closed).
The starting circuit cut-off relay prevents the starter motor from operating when neither of these con-
ditions has been met. In this instance, the starting ci rcuit cut-off relay is open so current cannot reach
the starter motor. When at least one of the above conditions has been met the starting circuit cut-off
relay is closed and the engine can be started by pressing the start switch.

ELECTRIC STARTING SYSTEM
9-9
a. WHEN THE TRANSMISSION IS IN NEU-TRAL
b. WHEN THE CLUTCH LEVER IS PULLED TO THE HANDLEBAR
1. Battery
2. Main fuse
3. Main relay
4. Starting circuit cut-off relay
5. Start switch
6. Diode
7. Clutch switch
8. Neutral switch
9. Starter relay
10.Starter motor

ELECTRIC STARTING SYSTEM
9-10
EAS2GC1363TROUBLESHOOTING
The starter motor fails to turn.
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 cover1. Check the fuse. Refer to “CHECKING THE FUSES”
on page 9-68. NG

Replace the fuse(s).
OK 
2. Check the battery. Refer to “CHECKING AND
CHARGING THE BATTERY” on
page 9-69. NG

• Clean the battery terminals.
• Recharge or replace the battery.
OK 
3. Check the starter motor operation. Refer to “CHECKING THE START-
ER MOTOR OPERATION” on page
9-75. OK

Starter motor is OK. Perform the electric
starting system troubleshooting, starting
with step 5.
NG 
4. Check the starter motor. Refer to “CHECKING THE START-
ER MOTOR” on page 6-38. NG

Repair or replace the starter motor.
OK 
5. Check the relay unit (Starting circuit cut-off relay).
Refer to “CHECKING THE RE-
LAYS” on page 9-72. NG

Replace the relay unit.
OK 
6. Check the diode. Refer to “CHECKING THE DIODE”
on page 9-73. NG

Replace the diode.
OK 
7. Check the starter relay. Refer to “CHECKING THE RE-
LAYS” on page 9-72. NG

Replace the starter relay.
OK 

ELECTRIC STARTING SYSTEM
9-11
8. Check the main relay.Refer to “CHECKING THE RE-
LAYS” on page 9-72. NG

Replace the main relay.
OK 
9. Check the neutral switch. Refer to “CHECKING THE
SWITCHES” on page 9-64. NG

Replace the neutral switch.
OK 
10.Check the clutch switch. Refer to “CHECKING THE
SWITCHES” on page 9-64. NG

Replace the clutch switch.
OK 
11.Check the engine stop switch. Refer to “CHECKING THE
SWITCHES” on page 9-64. NG

Replace the engine stop switch.
OK 
12.Check the start switch. Refer to “CHECKING THE
SWITCHES” on page 9-64. NG

Replace the start switch.
OK 
13.Check the entire starting system’s wiring.
Refer to “CIRCUIT DIAGRAM” on
page 9-6. NG

Properly connect or repair the starting sys-
tem’s wiring.
OK 
Replace the ECU.