Yamaha Wr250r 2008 Manual

 
ELECTRICAL COMPONENTS 
8-80 
sor shaft, check that the throttle position sen-
sor voltage is within the specified range.
The voltage does not change or it changes
abruptly  
→ 
 Replace the throttle position sen-
sor.

 
EAS28360 
CHECKING THE EXUP SERVO MOTOR 
1. Check: 
 
EXUP servo motor operation
Out of specification  
→ 
 Replace.

 
a. Disconnect the EXUP cables from the EXUP
servo motor pulley.
b. Disconnect the EXUP servo motor...

 
ELECTRICAL COMPONENTS 
8-81 
sensor to strong shocks. If the intake air 
temperature sensor is dropped, replace it. 
2. Check: 
 
Intake air temperature sensor resistance
Out of specification  
→ 
 Replace.

 
a. Connect the pocket tester ( 
Ω 
  
× 
 1k) to the in-
take air temperature sensor terminal as
shown.

 
EAS32D1013 
CHECKING THE INTAKE SOLENOID 
1. Check: 
 
Intake solenoid resistance
Out of specification  
→ 
 Replace....

 
1
2
3
4
5
6
7
8
9
 
TROUBLESHOOTING 
TROUBLESHOOTING ...................................................................................9-1  
GENERAL INFORMATION ......................................................................9-1
STARTING FAILURES.............................................................................9-1
INCORRECT ENGINE IDLING SPEED ...................................................9-1
POOR MEDIUM-AND-HIGH-SPEED PERFORMANCE ..........................9-2
FAULTY GEAR...

 
TROUBLESHOOTING 
9-1 
EAS28450 
TROUBLESHOOTING 
EAS28460 
GENERAL INFORMATION
NOTE:
 
The following guide for troubleshooting does not
cover all the possible causes of trouble. It should
be helpful, however, as a guide to basic trouble-
shooting. Refer to the relative procedure in this
manual for checks, adjustments, and replace- 
ment of parts. 
EAS28470 
STARTING FAILURES
Engine 
1. Cylinder (s) and cylinder head (s) 
 
Loose spark plug 
 
Loose cylinder head or cylinder 
 
Damaged cylinder head...

 
TROUBLESHOOTING 
9-2 
 
Faulty spark plug cap
3. Ignition coil (s) 
 
Faulty ignition coil 
 
Cracked or broken ignition coil
4. Ignition system 
 
ECU failure. 
 
Faulty crankshaft position sensor 
EAS28520 
POOR MEDIUM-AND-HIGH-SPEED 
PERFORMANCE 
Refer to “STARTING FAILURES” on page 9-1. 
Engine 
1. Air filter 
 
Clogged air filter element 
Fuel system 
1. Fuel pump 
 
Faulty fuel pump
2. Throttle body 
 
Defective throttle body
3. ECU 
 
ECU failure. 
EAS28530 
FAULTY GEAR SHIFTING...

 
TROUBLESHOOTING 
9-3 
 
Clogged air filter element 
Chassis 
1. Brake (s) 
 
Dragging brake 
Electrical system 
1. Spark plug (s) 
 
Incorrect spark plug gap 
 
Incorrect spark plug heat range
2. Ignition system 
 
ECU failure 
 
Faulty radiator fan motor relay 
 
Faulty coolant temperature sensor 
EAS28610 
OVERCOOLING
Cooling system 
1. Thermostat 
 
Thermostat stays open 
EAS28620 
POOR BRAKING PERFORMANCE 
 
Worn brake pad 
 
Worn brake disc 
 
Air in hydraulic brake system 
 
Leaking...

 
TROUBLESHOOTING 
9-4 
 
Faulty main switch 
 
Headlight bulb life expired 
Tail/brake light does not come on 
 
Too many electrical accessories 
 
Incorrect connection 
Turn signal does not come on 
 
Fuse open circuit 
 
Faulty turn signal switch 
 
Faulty turn signal relay 
 
Burnt-out turn signal bulb 
 
Incorrect connection 
 
Damaged or faulty wire harness 
 
Improperly grounded circuit 
 
Faulty battery 
 
Blown, damaged or incorrect fuse 
Turn signal blinks slowly 
 
Faulty turn...

 
TROUBLESHOOTING 
9-5 

 
EAS28740 
WIRING DIAGRAM
WR250R(X)/WR250X(X) 
2008 WIRING DIAGRAM 
1.AC magneto
2.Rectifier/regulator
3.Main switch
4.Battery
5.Main fuse
6.Starter relay
7.Starter motor
8.Right handlebar switch
9.Engine stop switch
10.Start switch
11.Relay unit
12.Sidestand switch
13.Neutral switch
14.Clutch switch
15.Fuel pump
16.ECU (electronic control unit)
17.Ignition coil
18.Spark plug
19.Intake solenoid
20.Fuel injector
21.Air induction solenoid
22.Intake air temperature sensor
23.Coolant temperature sensor...