engine YAMAHA WR 450F 2016 Owners Manual

ELECTRICAL COMPONENTS
9-80
c. Start the engine.
d. Measure the throttle position sensor input voltage.
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EAS2GC1403CHECKING THE INTAKE AIR PRESSURE
SENSOR
1. Check:
• Intake air pressure sensor output voltageOut of specification  Replace.
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a. Connect the pocket tester (20 VDC) to the
intake air pressure sensor coupler (wire har-
ness side). b. Start the engine.
c. Measure the intake air pressure sensor out-
put voltage.
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EAS2GC1404CHECKING THE INTAKE AIR TEMPERA-
TURE SENSOR
1. Remove:• Intake air temperature sensor(from the air filter case)
EWA
WARNING
• Handle the intake air temperature sensor with special care.
• Never subject the intake air temperature sensor to strong shocks. If the intake air
temperature sensor is dropped, replace it.
2. Check: • Intake air temperature sensor resistanceOut of specification  Replace.
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a. Connect the pocket tester (  1k/100) to
the intake air temperature sensor terminal.
• Positive tester probe 
Blue “1”
• Negative tester probe 
Black/Blue “2”
Intake air pressure sensor output
voltage3.61–3.67 V at 101.3 kPa (3.61–
3.67 V at 1.01kgf/cm
2, 3.61–3.67
V at 14.7 psi)
Pocket tester 90890-03112
Analog pocket tester YU-03112-C
• Positive tester probe 
Pink “1”
• Negative tester probe 
Black/Blue “2”
21
Intake air temperature sensor re-
sistance 290–390  at 80 °C (290–390 
at 176 °F)
Pocket tester 90890-03112
Analog pocket tester YU-03112-C
• Positive tester probe  Brown/White “1”
• Negative tester probe 
Black/Blue “2”
12

10
TROUBLESHOOTING
TROUBLESHOOTING.................................................................................... 10-1
GENERAL INFORMATION ...................................................................... 10-1
STARTING FAILURES ............................................................................. 10-1
INCORRECT ENGINE IDLING SPEED ................................................... 10-1
POOR MEDIUM-AND-HIGH-SPEED PERFORMANCE .......................... 10-2
SHIFTING IS DIFFICULT ......................................................................... 10-2
SHIFT PEDAL DOES NOT MOVE ........................................................... 10-2
JUMPS OUT OF GEAR............................................................................ 10-2
CLUTCH SLIPS ........................................................................................ 10-2
CLUTCH DRAGS ..................................................................................... 10-2
OVERHEATING ....................................................................................... 10-2
OVERCOOLING ....................................................................................... 10-3
POOR BRAKING PERFORMANCE ......................................................... 10-3
FRONT FORK OIL LEAKING ................................................................... 10-3
FAULTY FRONT FORK LEGS ................................................................. 10-3
UNSTABLE HANDLING ........................................................................... 10-3
HEADLIGHT DOES NOT COME ON ....................................................... 10-4
HEADLIGHT BULB BURNT OUT............................................................. 10-4
TAILLIGHT DOES NOT COME ON ......................................................... 10-4
LIST OF SELF-DIAGNOSTIC AND FAIL-SAFE ACTIONS ........................... 10-5

TROUBLESHOOTING
10-1
EAS2GC1406
TROUBLESHOOTING
EAS2GC1407GENERAL INFORMATION
TIP
The following guide for troubleshooting does
not cover all the possible causes of trouble. It
should be helpful, however, as a guide to basic
troubleshooting. Refer to the relative procedure
in this manual for checks, adjustments, and re-
placement of parts.
EAS2GC1408STARTING FAILURES
Engine
1. Cylinder and cylinder head• Loose spark plug
• Loose cylinder head or cylinder
• Damaged cylinder head gasket
• Damaged cylinder gasket
• Worn or damaged cylinder
• Incorrect valve clearance
• Improperly sealed valve
• Incorrect valve-to-valve-seat contact
• Incorrect valve timing
• Faulty valve spring
• Seized valve
2. Piston and piston ring(s) • Improperly installed piston ring
• Damaged, worn or fatigued piston ring
• Seized piston ring
• Seized or damaged piston
3. Air filter • Improperly installed air filter
• Clogged air filter element
4. Crankcase and crankshaft • Improperly assembled crankcase
• Seized crankshaft
Fuel system
1. Fuel tank • Empty fuel tank
• Clogged fuel tank breather hose
• Deteriorated or contaminated fuel
• Clogged or damaged fuel hose
2. Fuel pump
• Faulty fuel pump
3. Throttle body • Deteriorated or contaminated fuel
• Sucked-in air Electrical system
1. Battery
• Discharged battery
• Faulty battery
2. Fuse • Blown, damaged or incorrect fuse
• Improperly installed fuse
3. Spark plug • Incorrect spark plug gap
• Incorrect spark plug heat range
• Fouled spark plug
• Worn or damaged electrode
• Worn or damaged insulator
4. Ignition coil • Cracked or broken ignition coil body
• Broken or shorted primary or secondary coils
5. Ignition system • Faulty ECU
• Faulty crankshaft position sensor
• Broken generator rotor woodruff key
6. Switches and wiring
• Faulty ECU
• Faulty engine stop switch
• Broken or shorted wiring
• Faulty neutral switch
• Improperly grounded circuit
• Loose connections
7. Starting system • Faulty starter motor
• Faulty starter relay
• Faulty starting circuit cut-off relay
• Faulty starter clutch
EAS2GC1409INCORRECT ENGINE IDLING SPEED
Engine
1. Cylinder and cylinder head• Incorrect valve clearance
• Damaged valve train components
2. Air filter • Clogged air filter element
Fuel system
1. Throttle body • Damaged or loose throttle body joint
• Improperly synchronized throttle bodies
• Improper throttle cable free play
• Flooded throttle body

TROUBLESHOOTING
10-2
Electrical system
1. Battery• Discharged battery
• Faulty battery
2. Spark plug • Incorrect spark plug gap
• Incorrect spark plug heat range
• Fouled spark plug
• Worn or damaged electrode
• Worn or damaged insulator
• Faulty spark plug cap
3. Ignition coil
• Broken or shorted primary or secondary coil
• Cracked or broken ignition coil
4. Ignition system • Faulty ECU
• Faulty crankshaft position sensor
• Broken generator rotor woodruff key
EAS2GC1410POOR MEDIUM-AND-HIGH-SPEED PER-
FORMANCE
Refer to “STARTING FAILURES” on page 10-
1.
Engine
1. Air filter
• Clogged air filter element
Fuel system
1. Fuel pump • Faulty fuel pump
2. Throttle body
• Defective throttle body
3. ECU • Faulty ECU
EAS2GC1411SHIFTING IS DIFFICULT
Refer to “CLUTCH” on page 6-41.
EAS2GC1412SHIFT PEDAL DOES NOT MOVE
Engine
1. Shift shaft
• Bent shift shaft
2. Shift drum and shift forks • Foreign object in a shift drum groove
• Seized shift fork
• Bent shift fork guide bar
3. Transmission
• Seized transmission gear
• Foreign object between transmission gears
• Improperly assembled transmission
EAS2GC1413
JUMPS OUT OF GEAR
Engine
1. Shift shaft• Incorrect shift pedal position
• Improperly returned stopper lever
2. Shift forks
• Worn shift fork
3. Shift drum • Incorrect axial play
• Worn shift drum groove
4. Transmission • Worn gear dog
EAS2GC1414CLUTCH SLIPS
Engine
1. Clutch• Improperly assembled clutch
• Loose or fatigued clutch spring
• Worn friction plate
• Worn clutch plate
2. Engine oil
• Incorrect oil level
• Incorrect oil viscosity (low)
• Deteriorated oil
EAS2GC1415CLUTCH DRAGS
Engine
1. Clutch• Unevenly tensioned clutch springs
• Warped pressure plate
• Bent clutch plate
• Swollen friction plate
• Bent clutch push rod
• Damaged clutch boss
• Burnt primary driven gear bushing
2. Engine oil • Incorrect oil level
• Incorrect oil viscosity (high)
• Deteriorated oil
EAS2GC1416OVERHEATING
Engine
1. Cylinder head and piston• Heavy carbon buildup
• Clogged coolant passages
2. Engine oil
• Incorrect oil level
• Incorrect oil viscosity
• Inferior oil quality

LIST OF SELF-DIAGNOSTIC AND FAIL-SAFE ACTIONS
10-6
SENSOR OPERATION TABLEDiag-
nostic code No. Item Display Procedure
01 Throttle position sensor sig- nal
• Fully closed position
• Fully opened position • 11–14
• 109–116 • Check with throttle valve
fully closed.
• Check with throttle valve fully open.
03 Intake air pressure Displays the intake air pres- sure.Operate the throttle while
pushing the start switch. (If
the display value changes,
the performance is OK.)
05 Intake air temperature Displays the intake air tem- perature.Compare the actually mea-
sured intake air tempera-
ture with the Yamaha
diagnostic tool display val-
ue.
06 Coolant temperature When engine is cold: Dis- plays temperature closer to
air temperature.
When engine is hot: Displays
current coolant temperature.Compare the actually mea-
sured coolant temperature
with the Yamaha diagnostic
tool display value.
07 Vehicle speed pulses Vehicle speed pulse 0–999Check that the number in-
creases when the front
wheel is rotated. The num-
ber is cumulative and does
not reset each time the
wheel is stopped.
08 Lean angle sensor • Upright
• Overturned Displays the output voltage.
• 0.4–1.4
• 3.7–4.4 Remove the lean angle
sensor, and incline it more
than 45 degrees.
09 Monitor voltage Displays the fuel system volt- age.
• Approximately 12.0 (V)—
21 Neutral switch • Gear in neutral
• Gear not in neutral •ON
•OFF Operate the shift pedal.
60 EEPROM fault code display • No fault
• CO adjustment value
• Setting tool adjustment values 0–8 for fuel injec-
tion amount or ignition tim-
ing •00
•01
•07
—
61 Malfunction history ( ) code No. display *1
• There is no history.
• There is some history. •00
• Other: Displays the fault
code of ( ). —

EAS2GC1427
WIRING DIAGRAM
WR450F/WR450FG 2016
1. Joint connector
2. Joint connector
3. Joint connector
4. AC magneto
5. Rectifier/regulator
6. Headlight relay
7. Main relay
8. Engine ground
9. Battery
10. Frame ground
11. Starter relay
12. Main fuse
13. Starter motor
14. Starter relay diode
15. Indicator light
16. Engine trouble warning light
17. Fuel level warning light
18. Resistor
19. Fuel sender
20. Diode
21. Coupler for connecting option-al part
22. ECU (engine control unit)
23. Ignition coil
24. Spark plug
25. Injector
26. Fuel pump
27. Radiator fan motor relay
28. Radiator fan motor fuse
29. Radiator fan motor
30. Joint connector
31. Intake air temperature sensor
32. Coolant temperature sensor
33. Throttle position sensor
34. Intake air pressure sensor
35. Lean angle sensor
36. Engine stop switch
37. Neutral switch
38. Diode
39. Starting circuit cut-off relay
40. Clutch switch
41. Start switch
42. Joint connector
43. Taillight
44. Headlight
45. Coupler for connecting option- al switch
46. Speed sensor
47. Multi-function display
48. Frame ground
49. Ignition coil sub-lead
50. Negative battery lead
51. Engine ground sub-lead
EAS2GC1428
COLOR CODE
BBlack
Br Brown
Ch Chocolate
Dg Dark green
G Green
Gy Gray
LBlue
Lg Light green
O Orange
PPink
RRed
Sb Sky blue
WWhite
Y Yellow
B/L Black/Blue
B/O Black/Orange
B/W Black/White
B/Y Black/Yellow
Br/W Brown/White
G/B Green/Black
G/W Green/White
G/Y Green/Yellow
L/B Blue/Black
L/G Blue/Green
L/R Blue/Red
L/W Blue/White
L/Y Blue/Yellow
P/L Pink/Blue
R/B Red/Black
R/L Red/Blue
R/W Red/White
R/Y Red/Yellow
W/B White/Black
Y/B Yellow/Black
Y/G Yellow/Green
Y/R Yellow/Red