2016 YAMAHA WR 450F cooling

ENGINE
3-11
3. Remove:• Radiator capSlowly loosen the radiator cap to drain cool-
ant.
TIP
When the radiator cap is loosened, coolant will
gush out transversely; therefore, bring the con-
tainer near to the outlet.
4. Thoroughly flush the cooling system with
clean tap water.
5. Install:
• Copper washer
• Coolant drain bolt
6. Pour coolant.
EWA
WARNING
• If coolant splashes in your eyes, thorough- ly wash them with water and consult a
doctor.
• If coolant splashes on your clothes, quick-
ly wash it away with water and then with
soap and water.
• If coolant is swallowed, induce vomiting
and get immediate medical attention.
ECA
NOTICE
• Adding water instead of coolant lowers the
antifreeze content of the coolant. If water
is used instead of coolant check, and if
necessary, correct the antifreeze concen-
tration of the coolant.
• Use only distilled water. However, if dis-
tilled water is not available, soft water may
be used.
• If coolant comes into contact with painted
surfaces, immediately wash them with wa-
ter.
• Do not mix different types of antifreeze.
7. Install:• Radiator cap 8. Start the engine, warm this up for 3 minutes,
stop it, and then wait for it to cool down.
TIP
This model is equipped with an engine auto-
stop system. The engine stops automatically if
left idling for 7 minutes. If the engine stops,
push the start switch or push down the kick-
starter lever to restart the engine.
9. Check:• Coolant levelRefer to “CHECKING THE COOLANT LEV-
EL” on page 3-10.
EAS2GC1085CHECKING THE RADIATOR CAP
1. Check:• Seal (radiator cap) “1”
• Valve and valve seat “2”
Crack/damage  Replace.
Exist fur deposits  Clean or replace.
EAS2GC1086CHECKING THE RADIATOR CAP VALVE
OPENING PRESSURE
1. Check:
• Radiator cap valve opening pressure
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Install the radiator cap tester adapter “2” and the radiator cap tester “3” to the radiator cap
“1,” and activate the tester to check whether
it can stay for 5 to 10 seconds within stan-
dard pressure values.
TIP
Before attaching the cap to the tester, apply
water to its sealing surface.
No stay  Replace.
Coolant drain bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Recommended coolant High quality ethylene glycol
anti-freeze containing anti-cor-
rosion for aluminum engine
Radiator (including all routes) 1.03 L (1.09 US qt, 0.91 Imp.qt)
Coolant mixing ratio 1:1 (Coolant:Water)
New
T R..
Radiator cap valve opening pres-
sure 107.9–137.3 kPa (1.08–1.37 kg/
cm
2,15.6–19.9 psi)

ENGINE
3-12
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EAS2GC1087CHECKING THE COOLANT CIRCULATORY
SYSTEM FOR LEAKS
1. Check:• Coolant level
2. Install: • Radiator cap tester “1”
• Adapter “2”
3. Activate the tester to apply the test pressure.
ECA
NOTICE
• Do not apply such a high pressure as ex- ceeds the test pressure.
• Make sure that a checkup after the cylin-
der head gasket is replaced is made after 3
minutes of warm-up.
• Make sure that coolant is filled up to the
upper level beforehand.
TIP
This model is equipped with an engine auto-
stop system. The engine stops automatically if
left idling for 7 minutes. If the engine stops,
push the start switch or push down the kick-
starter lever to restart the engine.
4. Check:
• Pressure valueNo stay for 5 to 10 seconds at the test pres-
sure value  Correct.
• Radiator
• Radiator hose connections Coolant leaks  Correct or replace.
• Radiator hoses Bulges  Replace
EWA
WARNING
When the radiator cap tester is removed,
coolant will spout; therefore, cover it with a
cloth beforehand.
EAS2GC1088ADJUSTING THE CLUTCH LEVER FREE
PLAY
1. Check:
• Clutch lever free play “a”Out of specification  Regulate.
Radiator cap tester
90890-01325
Mityvac cooling system tester kit YU-24460-A
Radiator cap tester adapter 90890-01352
Pressure tester adapter YU-33984
Radiator cap tester 90890-01325
Mityvac cooling system tester kit YU-24460-A
Radiator cap tester adapter 90890-01352
Pressure tester adapter YU-33984
Test pressure value 196 kPa (1.96 kg/cm
2, 27.9 psi)
Clutch lever free play 7.0–12.0 mm (0.28–0.47 in)

7
COOLING SYSTEM
RADIATOR....................................................................................................... 7-1
HANDLING NOTE ...................................................................................... 7-3
CHECKING THE RADIATOR ..................................................................... 7-3
WATER PUMP .................................................................................................. 7-4
REMOVING THE OIL SEAL ....................................................................... 7-5
CHECKING THE WATER PUMP ............................................................... 7-5
CHECKING THE BEARING ....................................................................... 7-5
INSTALLING THE OIL SEAL ..................................................................... 7-5
ASSEMBLING THE WATER PUMP........................................................... 7-5

9
ELECTRICAL SYSTEM
IGNITION SYSTEM.......................................................................................... 9-2
CIRCUIT DIAGRAM ................................................................................... 9-2
TROUBLESHOOTING ............................................................................... 9-4
ELECTRIC STARTING SYSTEM ..................................................................... 9-6
CIRCUIT DIAGRAM ................................................................................... 9-6
STARTING CIRCUIT CUT-OFF SYSTEM OPERATION ........................... 9-8
TROUBLESHOOTING ............................................................................. 9-10
CHARGING SYSTEM ..................................................................................... 9-12
CIRCUIT DIAGRAM ................................................................................. 9-12
TROUBLESHOOTING ............................................................................. 9-14
LIGHTING SYSTEM ....................................................................................... 9-16
CIRCUIT DIAGRAM ................................................................................. 9-16
TROUBLESHOOTING ............................................................................. 9-18
SIGNALING SYSTEM .................................................................................... 9-20
CIRCUIT DIAGRAM ................................................................................. 9-20
TROUBLESHOOTING ............................................................................. 9-22
COOLING SYSTEM ........................................................................................ 9-24
CIRCUIT DIAGRAM ................................................................................. 9-24
TROUBLESHOOTING ............................................................................. 9-26
FUEL INJECTION SYSTEM ........................................................................... 9-28
CIRCUIT DIAGRAM ................................................................................. 9-28
ECU SELF-DIAGNOSTIC FUNCTION ..................................................... 9-30
TROUBLESHOOTING METHOD ............................................................. 9-31
YAMAHA DIAGNOSTIC TOOL ................................................................ 9-32
TROUBLESHOOTING DETAILS ............................................................. 9-35
FUEL PUMP SYSTEM .................................................................................... 9-56
CIRCUIT DIAGRAM ................................................................................. 9-56
TROUBLESHOOTING ............................................................................. 9-58

COOLING SYSTEM
9-24
EAS2GC1370
COOLING SYSTEM
EAS2GC1371CIRCUIT DIAGRAM
ONOFF
ONOFF
BBB
BBB
RRR
RRR/L
Br Br BrBr Br
(Gy)
(Gy)B/LGyWW W BGy
BR
WW W
BR
R,R/Y
G
R
Y/B
R,R/W
Br
RL/R
(B)R/YR/WBr/WL/G
Br/W,BrL/W
(B)
(B) Br BrL/Y
Y/R
G/YBrBB
BrBrL/YY/W
(B) (B)B BGG/Y
RR/L
RLg
W/B
(B)
BGyBr RW/BB/LLYP
G/WB/Y
R/BLgG/YW
Br/W
OL/RY/BB/OL/BSbY/R
L/Y P/L
Y/G
(Gy)R/L R/BR/LB/Y
R/WR/L
R/W,BrP/L
R/L R/L
(B)
(B) (B)
(L)
(L) (B)
BR/LLBR/L R/L R/L R/L R/L B/L B/L B/L B/L B/L B/L B/LLLLLBBBB
Br Br Br Br
B/LBr/W
B/LG/WLYB/L
B/LPLB/LY/GL
(B)
(B)B/OBBBSbW/B
Sb
SbG/B
L/G,L/WL/BBrG/BG/BB
BB
(B)
(B)L/BBBB
Br Br
Br BrBr
BB
LY
(B)
(B)
(B)
(B)
(B)
GB
ChDg YB
BRW
BrRBW
B/WRW
Ch DgYBBrR/WBW
R
O
OR/L
BB
B
B
BBBBBB
RRRRRR/L
BrBrBrBrBr
Br
Br
BrBrBrBrR/LR/LR/LR/LR/L
B
LLLP
PL
Y
Y
RR
Br
R/LR/L
R/L
P/L
P/L
R/L
R/L
R/LR/B
R/B
L/RL/Y
L/Y
Y/R
Y/R
G/Y
G/YG/Y
G/Y
B/Y
B/Y
R/LB/LB/L
B/LB/LB/LY/G
Y/GB/L
B/OL/BY/BW/B
W/B
G/B
L/B
W/BW/B
L/BL/BL/GL/W
L/W
L/R
Br/W
Br/W
R/W
R/W
R/Y
R/Y
G/BG/B
G/B
B/O
B/LB/LB/LB/LB/LB/LB/L
G/W
G/W
Br/W
Br/W
R/WR/WBr
O
O
RGy
LLLLBBBB
B
B
B
B
BB
B
B
RRWW
Y
Y
Dg
Dg
Ch
Ch
RW
BrBrBrBr
Br
B
W
Sb
SbSb
SbBr
Br
B
Br
Lg
Lg
R/L
R
R
RR
Gy
BB
WWWWWW
R
RRGGBB
B
Y/B
BB
Br
Br
Br
L/G
B/L
B/WB/W
OR
OR
RBBB
B
BBBBB

COOLING SYSTEM
9-25
1. Joint connector
2. Joint connector
3. Joint connector
7. Main relay
9. Battery
10.Frame ground
11.Starter relay
12.Main fuse
22.ECU (engine control unit)
27.Radiator fan motor relay
28.Radiator fan motor fuse
29.Radiator fan motor
30.Joint connector
32.Coolant temperature sensor
48.Frame ground
50.Negative battery lead

COOLING SYSTEM
9-26
EAS2GC1372TROUBLESHOOTING
The radiator fan motor fails to turn.
TIP
Before troubleshooting, remove the following part(s):
1. Seat
2. Side cover (left)
3. Air scoop (left/right)
4. Fuel tank1. 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 main relay. Refer to “CHECKING THE RE-
LAYS” on page 9-72. NG

Replace the main relay.
OK 
4. Check the radiator fan motor. Refer to “CHECKING THE RADIA-
TOR FAN MOTOR” on page 9-78. NG

Replace the radiator fan motor.
OK 
5. Check the radiator fan motor relay. Refer to “CHECKING THE RE-
LAYS” on page 9-72. NG

Replace the radiator fan motor relay.
OK 
6. Check the coolant temperature sen- sor.
Refer to “CHECKING THE COOL-
ANT TEMPERATURE SENSOR”
on page 9-78. NG

Replace the coolant temperature sensor.
OK 
7. Check the entire cooling system’s wiring.
Refer to “CIRCUIT DIAGRAM” on
page 9-16. NG

Properly connect or repair the cooling sys-
tem’s wiring.
OK 
Replace the ECU.

COOLING SYSTEM
9-27
EAS2GC1373