2016 YAMAHA WR 450F ignition

ELECTRICAL COMPONENTS
9-61
1. Rectifier/regulator
2. Clutch switch
3. Ignition coil
4. ECU (engine control unit)
5. Fuel sender
6. Fuel pump
7. Battery
8. Resistor
9. Neutral switch
10.Radiator fan motor
11.Injector

ELECTRICAL COMPONENTS
9-68
Checking the condition of the bulb sockets
The following procedure applies to all of the
bulb sockets.
1. Check:• Bulb socket (for continuity)(with the pocket tester)
No continuity  Replace.
TIP
Check each bulb socket for continuity in the
same manner as described in the bulb section;
however, note the following.
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a. Install a good bulb into the bulb socket.
b. Connect the pocket tester probes to the re-
spective leads of the bulb socket.
c. Check the bulb socket for continuity. If any of
the readings indicate no continuity, replace
the bulb socket.
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EAS2GC1385CHECKING THE FUSES
The following procedure applies to all of the
fuses.
ECA
NOTICE
To avoid a short circuit, always turn off the
meter when checking or replacing a fuse.
1. Remove: • Side cover (left/right)
• SeatRefer to “GENERAL CHASSIS” on page 5-
1.
2. Check: • Main fuse “1”
• Radiator fan motor fuse “2”
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a. Connect the pocket tester to the fuse and check the continuity.
TIP
Set the pocket tester selector to “ 1”.
b. If the pocket tester indicates “ ”, replace the
fuse.
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3. Replace: • Fuse
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a. The meter light goes off.
b. Install a new fuse of the correct amperage rating.
c. Turn on the meter light to verify if the electri- cal circuit is operational.
d. If the fuse immediatel y blows again, check
the electrical circuit.
EWA
WARNING
Never use a fuse with an amperage rating
other than that specified. Improvising or us-
ing a fuse with the wrong amperage rating
may cause extensive damage to the electri-
cal system, cause the lighting and ignition
systems to malfunction and could possibly
cause a fire.
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Pocket tester 90890-03112
Analog pocket tester YU-03112-C
1
Pocket tester90890-03112
Analog pocket tester YU-03112-C
Fuses Amper-
age rating Q’ty
Main 15 A 1
Spare 15 A 1
Radiator fan motor 5 A 1
2

ELECTRICAL COMPONENTS
9-73
EAS2GC1388CHECKING THE DIODE
1. Check:•DiodeOut of specification  Replace.
TIP
The pocket tester and the analog pocket tester
readings are shown in the following table.
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a. Disconnect the diode from the wire harness.
b. Connect the pocket tester (  1) to the di-
ode coupler as shown.
c. Check the diode for continuity.
d. Check the diode for no continuity.
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EAS2GC1389CHECKING THE IGNITION SPARK GAP
1. Check: • Ignition spark gapOut of specification  Perform the ignition
system troubleshooting, starting with step 4.
Refer to “TROUBLESHOOTING” on page 9-
4.
TIP
If the ignition spark gap is within specification,
the ignition system circui t is operating normally.
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a. Remove the spark plug cap from the spark
plug.
b. Connect the ignition checker “1” as shown.
c. Push the engine stop switch.
d. Measure the ignition spark gap “a”.
e. Crank the engine by pushing the start switch and gradually increase the spark gap until a
misfire occurs.
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EAS2GC1390CHECKING THE SPARK PLUG CAP
1. Remove:• Spark plug cap
(from the spark plug lead)
2. Check: • Spark plug cap resistance
Out of specification  Replace.
Result
Continuity
(between “3” to “4”)
Pocket tester 90890-03112
Analog pocket tester YU-03112-C
No continuity Tester positive lead  Sky blue
“1”
Tester negative lead  Green/
Black “2”
Continuity Tester positive lead  Green/
Black “2”
Tester negative lead  Sky blue
“1”
No continuity Tester positive lead  Red “3”
Tester negative lead  Red/Blue
“4”
Continuity Tester positive lead  Red/Blue
“4”
Tester negative lead  Red “3”
2
1
4
3
R
Sb
G/B R/L
Minimum ignition spark gap 6.0 mm (0.24 in)
Ignition checker 90890-06754
Oppama pet–4000 spark checker YM-34487
2. Spark plug cap
Resistance 7.50–12.50 k 

ELECTRICAL COMPONENTS
9-74
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a. Connect the pocket tester ( 1k) to the
spark plug cap.
b. Measure the spark plug cap resistance.
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EAS2GC1391CHECKING THE IGNITION COIL
1. Disconnect: • Ignition coil terminal(from the sub wire harness)
• Spark plug cap (from the ignition coil)
2. Check:
• Primary coil resistanceOut of specification  Replace.
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a. Connect the pocket tester (  1) to the igni-
tion coil. b. Measure the primary coil resistance.
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3. Check:
• Secondary coil resistanceOut of specification  Replace.
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a. Connect the pocket tester (  1k) to the ig-
nition coil.
b. Measure the secondary coil resistance.
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EAS2GC1392CHECKING THE CRANKSHAFT POSITION
SENSOR
1. Disconnect: • Crankshaft position sensor coupler(from the wire harness)
2. Check:
• Crankshaft position sensor resistanceOut of specification  Replace.
Pocket tester
90890-03112
Analog pocket tester YU-03112-C
Primary coil resistance 2.16–2.64 
Pocket tester 90890-03112
Analog pocket tester YU-03112-C
• Positive tester probe 
Ignition coil terminal 1 “1”
• Negative tester probe 
Ignition coil terminal 2 “2”
Secondary coil resistance 8.64–12.96 k 
Pocket tester 90890-03112
Analog pocket tester YU-03112-C
• Positive tester probe  Ignition coil terminal 1 “1”
• Negative tester probe 
Spark plug lead “2”

ELECTRICAL COMPONENTS
9-76
b. Check the starter motor operation.
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EAS28150CHECKING THE STATOR COIL
1. Disconnect:• Stator coil coupler(from the wire harness)
2. Check:
• Stator coil resistanceOut of specification  Replace the stator
coil.
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a. Connect the pocket tester (  1) to the sta-
tor coil coupler as shown. b. Measure the stator coil resistance.
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EAS2GC1395CHECKING THE RECTIFIER/REGULATOR
1. Check:
• Charging voltageOut of specification  Replace the rectifier/
regulator.
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a. Set the digital tachometer to the ignition coil.
b. Connect the pocket tester (DC 20 V) to the rectifier/regulator coupler as shown.
c. Start the engine and let it run at approxi- mately 5000 r/min.
d. Measure the charging voltage.
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Stator coil resistance 0.528–0.792  (W–W)
Pocket tester 90890-03112
Analog pocket tester YU-03112-C
• Positive tester probe 
White “1”
• Negative tester probe 
White “2”
• Positive tester probe  White “1”
• Negative tester probe 
White “3”
• Positive tester probe  White “2”
• Negative tester probe 
White “3”
No load regulated voltage 14.1–14.9 V
Digital tachometer 90890-06760
Digital tachometer YU-39951-B
Pocket tester 90890-03112
Analog pocket tester YU-03112-C
• Positive tester probe  Red “1”
• Negative tester probe 
Black “2”
123
12

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

TROUBLESHOOTING
10-3
Cooling system
1. Coolant• Low coolant level
2. Radiator • Damaged or leaking radiator
• Faulty radiator cap
• Bent or damaged radiator fin
3. Water pump • Damaged or faulty water pump
• Damaged hose
• Improperly connected hose
• Damaged pipe
• Improperly connected pipe
Fuel system
1. Throttle body • Damaged or loose throttle body joint
2. Air filter • Clogged air filter element
Chassis
1. Brake(s) • Dragging brake
Electrical system
1. Spark plug • Incorrect spark plug gap
• Incorrect spark plug heat range
2. Ignition system • Faulty ECU
• Faulty coolant temperature sensor
EAS2GC1417OVERCOOLING
Cooling system
1. Coolant temperature sensor• Faulty coolant temperature sensor
EAS2GC1418POOR BRAKING PERFORMANCE
Chassis
1. Brake(s)• Worn brake pad
• Worn brake disc
• Air in hydraulic brake system
• Leaking brake fluid
• Defective master cylinder kit
• Faulty brake caliper kit
• Faulty brake caliper seal
• Loose union bolt
• Damaged brake hose
• Oil or grease on the brake disc
• Oil or grease on the brake pad
• Incorrect brake fluid level
EAS2GC1419FRONT FORK OIL LEAKING
Chassis
1. Front fork• Bent, damaged, or rusty inner tube
• Cracked or damaged outer tube
• Improperly installed oil seal
• Damaged oil seal lip
• Incorrect oil level (high)
• Loose damper rod assembly bolt
• Damaged damper rod assembly bolt copper
washer
• Cracked or damaged cap bolt O-ring
EAS2GC1420FAULTY FRONT FORK LEGS
Chassis
1. Front fork • Bent or damaged inner tube
• Bent or damaged outer tube
• Broken fork spring
• Bent or damaged damper rod
• Incorrect oil viscosity
• Incorrect oil level
EAS2GC1421UNSTABLE HANDLING
Chassis
1. Handlebar• Bent or improperly installed handlebar
2. Steering head components • Improperly installed upper bracket
• Improperly installed lower bracket(improperly tightened ring nut)
• Bent steering stem
• Damaged ball bearing or bearing race
3. Front fork leg (s) • Uneven oil levels (both front fork legs)
• Unevenly tensioned fork spring (both front fork legs)
• Broken fork spring
• Bent or damaged inner tube
• Bent or damaged outer tube
4. Swingarm • Worn bearing or bushing
• Bent or damaged swingarm
5. Rear shock absorber assembly (-ies) • Faulty rear shock absorber spring
• Leaking oil or gas
6. Tire (s) • Uneven tire pressures (front and rear)
• Incorrect tire pressure
• Uneven tire wear