2016 YAMAHA WR 250F 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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EAS2GB7384CHECKING 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)
• Seat
Refer 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 immediately 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 tester
90890-03112
Analog pocket tester
YU-03112-C
FusesAmper-
age ratingQ’ty
Main 15 A 1
Spare 15 A 1
Radiator fan motor 5 A 1
2

ELECTRICAL COMPONENTS
9-73
EAS2GB7387CHECKING THE DIODE
1. Check:
•Diode
Out 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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EAS2GB7388CHECKING THE IGNITION SPARK GAP
1. Check:
• Ignition spark gap
Out 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 circuit 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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EAS2GB7389CHECKING 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
10.00 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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EAS2GB7390CHECKING THE IGNITION COIL
1. Disconnect:
• Ignition coil terminal
(from the sub wire harness)
• Spark plug cap
(from the ignition coil)
2. Check:
• Primary coil resistance
Out 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 resistance
Out 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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EAS2GB7391CHECKING THE CRANKSHAFT POSITION
SENSOR
1. Disconnect:
• Crankshaft position sensor coupler
(from the wire harness)
2. Check:
• Crankshaft position sensor resistance 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 resistance
Out 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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1. Check:
• Charging voltage
Out 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
EAS2GB7405
TROUBLESHOOTING
EAS2GB7406GENERAL 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.
EAS2GB7407STARTING 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. Spark plug
• Incorrect spark plug gap• Incorrect spark plug heat range
• Fouled spark plug
• Worn or damaged electrode
• Worn or damaged insulator
2. Ignition coil
• Cracked or broken ignition coil body
• Broken or shorted primary or secondary
coils
3. Ignition system
• Faulty ECU
• Faulty crankshaft position sensor
• Broken generator rotor woodruff key
4. Switches and wiring
• Faulty ECU
• Faulty engine stop switch
• Broken or shorted wiring
• Faulty neutral switch
• Improperly grounded circuit
• Loose connections
EAS2GB7408INCORRECT 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
Electrical system
1. 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
2. Ignition coil
• Broken or shorted primary or secondary
coils
• Cracked or broken ignition coil
3. Ignition system
• Faulty ECU
• Faulty crankshaft position sensor
• Broken generator rotor woodruff key

TROUBLESHOOTING
10-3
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
EAS2GB7416OVERCOOLING
Cooling system
1. Coolant temperature sensor
• Faulty coolant temperature sensor
EAS2GB7417POOR 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
EAS2GB7418FRONT 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
EAS2GB7419FAULTY 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
EAS2GB7420UNSTABLE 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
7. Wheel (s)
• Incorrect wheel balance
• Broken or loose spoke
• Damaged wheel bearing
• Bent or loose wheel axle
• Excessive wheel runout
8. Frame
• Bent frame
• Damaged steering head pipe
• Improperly installed bearing race

LIST OF SELF-DIAGNOSTIC AND FAIL-SAFE ACTIONS
10-5
EAS2GB7424
LIST OF SELF-DIAGNOSTIC AND FAIL-SAFE ACTIONS
LIST OF DIAGNOSTIC CODES
COMMUNICATION ERROR WITH YAMAHA DIAGNOSTIC TOOLFault
codeItem Page
12 Crankshaft position sensor: no normal signals are received from the
crankshaft position sensor.9-35
13 Intake air pressure sensor: open or short circuit detected. 9-37
14 Intake air pressure sensor: hose system malfunction (clogged or de-
tached hose)9-38
15 Throttle position sensor: open or short circuit detected. 9-39
16 Throttle position sensor: stuck throttle position sensor is detected. 9-41
21 Coolant temperature sensor: open or short circuit detected. 9-42
22 Intake air temperature sensor: open or short circuit detected. 9-43
30 Latch up detected. 9-44
33 Ignition coil: open or short circuit detected in the primary lead of the
ignition coil.9-45
39 Injector: open or short circuit detected. 9-47
41 Lean angle sensor: open or short circuit detected. 9-48
43 Fuel system voltage: incorrect voltage supplied to the fuel injector and
fuel pump.9-49
44 EEPROM fault code number: an error is detected while reading or
writing on EEPROM.9-50
46 Charging voltage is abnormal. 9-51
50 Faulty ECU memory. (When this malfunction is detected in the ECU,
the fault code number might not appear on the meter.)9-52
Fault
codeItem Page
Waiting
for con-
nectionNo communication signal is received from the ECU.
9-52
Er-2 Signals from the ECU cannot be received within the specified period
of time.9-53
Er-3 Data from the ECU cannot be received correctly. 9-54
Er-4 Registered data cannot be received from the Yamaha diagnostic tool. 9-55