2008 YAMAHA WR 250F check engine light

CONTENTS
CHAPTER 1GENERAL
INFORMATION
DESCRIPTION ................. 1-1
MACHINE
IDENTIFICATION ............. 1-2
INCLUDED PARTS .......... 1-2
IMPORTANT
INFORMATION................. 1-2
CHECKING OF
CONNECTION .................. 1-3
SPECIAL TOOLS ............. 1-4
CONTROL FUNCTIONS .. 1-8
MULTI-FUNCTION
DISPLAY .......................... 1-9
STARTING AND
BREAK-IN ...................... 1-14
TORQUE-CHECK
POINTS........................... 1-16
CLEANING AND
STORAGE ...................... 1-17
CHAPTER 2
SPECIFICATIONS
GENERAL
SPECIFICATIONS ............ 2-1
MAINTENANCE
SPECIFICATIONS ............ 2-3
TIGHTENING
TORQUES ...................... 2-11
LUBRICATION
DIAGRAMS .................... 2-18
CABLE ROUTING
DIAGRAM ....................... 2-21
CHAPTER 3 REGULAR
INSPECTION AND ADJUSTMENTS
MAINTENANCE
INTERVALS ...................... 3-1
PRE-OPERATION
INSPECTION AND
MAINTENANCE................ 3-5
ENGINE ............................ 3-6
CHASSIS ........................ 3-17
ELECTRICAL ................. 3-27
CHAPTER 4 TUNING
ENGINE ............................ 4-1
CHASSIS .......................... 4-5
CHAPTER 5ENGINE
RADIATOR ....................... 5-1
CARBURETOR................. 5-4
AIR INDICTOIN
SYSTEM ......................... 5-12
CAMSHAFTS.................. 5-14
CYLINDER HEAD........... 5-19
VALVES AND VALVE
SPRINGS ........................ 5-21
CYLINDER AND
PISTON ........................... 5-25
CLUTCH ......................... 5-29
OIL FILTER ELEMENT
AND WATER PUMP ....... 5-34
BALANCER .................... 5-38
OIL PUMP ....................... 5-40
KICK SHAFT AND
SHIFT SHAFT ................. 5-43
AC MAGNETO AND
STARTER CLUTCH ....... 5-48
ENGINE REMOVAL ....... 5-53 CRANKCASE AND
CRANKSHAFT ...............5-57
TRANSMISSION, SHIFT
CAM AND SHIFT FORK .5-63
CHAPTER 6
CHASSIS
FRONT WHEEL AND
REAR WHEEL ..................6-1
FRONT BRAKE AND
REAR BRAKE ..................6-6
FRONT FORK .................6-16
HANDLEBAR..................6-23
STEERING ......................6-27
SWINGARM ....................6-31
REAR SHOCK
ABSORBER ....................6-36
CHAPTER 7
ELECTRICAL
ELECTRICAL
COMPONENTS AND
WIRING DIAGRAM ...........7-1
IGNITION SYSTEM...........7-3
ELECTRIC STARTING
SYSTEM............................7-5
CHARGING SYSTEM .....7-13
THROTTLE POSITION
SENSOR SYSTEM .........7-15
LIGHTING SYSTEM .......7-18
SIGNALING SYSTEM.....7-20

1-1
DESCRIPTION
GENERAL INFORMATION
DESCRIPTION
• The machine you have purchased may differ slightly from those shown in the following.
• Designs and specifications are subject to change without notice.
1. Clutch lever
2. Hot starter lever
3. Engine stop switch
4. Multi-function display
5. Main switch
6. Start switch
7. Front brake lever
8. Throttle grip
9. Radiator cap
10. Fuel tank cap
11. Taillight
12. Kickstarter crank
13. Fuel tank 14. Headlight
15. Radiator
16. Coolant drain bolt
17. Rear brake pedal
18. Valve joint
19. Fuel cock
20. Cold starter knob
21. Air cleaner
22. Catch tank
23. Drive chain
24. Oil level check window
25. Shift pedal
26. Front fork
1

2-11
TIGHTENING TORQUES
TIGHTENING TORQUES
ENGINE
△- marked portion shall be checked for torque ti ghtening after break-in or before each race.
Normal output 14 V/120 W at 5,000 r/min----
Charging coil resistance (color) 0.288–0.432 Ω at 20 °C (68 °F) (White–
Ground) ----
Lighting coil resistance (color) 0.224–0.336 Ω at 20 °C (68 °F) (Yellow–
Ground) ----
Rectifier/regulator: Regulator type Semiconductor short circuit----
Model/manufacture SH770AA/SHINDENGEN----
Regulated voltage (AC) 12.5–13.5 V----
Regulated voltage (DC) 14.0–15.0 V----
Rectifier capacity (AC) 12 A----
Rectifier capacity (DC) 8 A----
Electric starting system: Type Constant mesh----
Starter motor: Model/manufacturer 5UM01/YAMAHA----
Operation voltage 12 V----
Output 0.35 kW----
Armature coil resistance 0.0189–0.0231 Ω at 20 °C (68 °F) ----
Brush overall length 7 mm (0.28 in)3.5 mm (0.14
in)
Brush quantity 2 pcs.----
Spring force 3.92–5.88 N (400–600 g, 14.1–21.2 oz) ----
Commutator diameter 17.6 mm (0.69 in)16.6 mm (0.65
in)
Mica undercut (depth) 1.5 mm (0.06 in) ----
Starter relay: Model/manufacturer 2768090-A/JIDECO----
Amperage rating 180 A----
Coil winding resistance 4.2–4.6 Ω at 20 °C (68 °F) ----
Starting circui t cut-off relay:
Model/manufacturer ACM33221 M38/MATSUSHITA ----
Coil winding resistance 75.69–92.51 Ω at 20 °C (68 °F) ----
Fuse (amperage×quantity): Main fuse 10 A × 1----
Reserve fuse 10 A × 1----
Item
StandardLimit
Part to be tightened Thread size Q'tyTightening torque
Nm m•kg ft•lb
Spark plug M10S × 1.0 1 13 1.3 9.4
Camshaft cap M6 × 1.0 10 10 1.0 7.2
Cylinder head blind plug screw M12 × 1.0 1 28 2.8 20
Cylinder head (stud bolt) M6 × 1.0 2 7 0.7 5.1

3-13
ENGINE
4. Remove:• Engine guard "1"
• Bolt (oil tank) "2"
• Washer "3"
• Oil filler cap "4"
• Oil tank drain bolt "5"
• Crankcase oil drain bolt "6"
• Oil filter element drain bolt "7"Drain the crankcase and oil tank
of its oil.
5. Remove: • Oil hose clamp "1"
• Bolt (oil hose)
• Oil hose "2"
• Oil strainer "3"
6. Inspect: • Oil strainerClogged →Blow.
7. If the oil filter is to be replaced dur-
ing this oil change, remove the fol-
lowing parts and reinstall them.
Replacement steps:
a. Remove the oil filter element cov-er "1" and oil filter element "2".
b. Check the O-rings "3", if cracked or damaged, replace them with a
new one.
c. Install the oil filter element and oil filter element cover.
8. Install:• O-ring "1"
• Oil strainer "2"
• Oil hose
• Bolt (oil hose)
• Oil hose clamp
9. Install: • Copper washer
• Oil filter element drain bolt
• Crankcase oil drain bolt
• Oil tank drain bolt
• Engine guard 10. Fill:
• Engine oil
11. Check: • Oil leakage
12. Install: • Oil filler cap
• Washer (oil tank)
• Bolt (oil tank)
13. Check: • Engine oil level
CHECKING THE OIL PRESSURE
1. Check: • Oil pressure
Checking steps:
a. Slightly loosen the oil pressure check bolt "1".
b. Start the engine and keep it idling
until oil starts to seep from the oil
pressure check bolt. If no oil
comes out after one minute, turn
the engine off so it will not seize.
c. Check oil passages and oil pump for damage or leakage.
d. Start the engine after solving the problem(s) and recheck the oil
pressure.
e. Tighten the oil pressure check bolt.
Oil filter element cover:10 Nm (1.0 m•kg, 7.2
ft•lb)
Oil strainer: 9 Nm (0.9 m•kg, 6.5
ft•lb)
Bolt (oil hose): 8 Nm (0.8 m•kg, 5.8
ft•lb)
Oil hose clamp: 2 Nm (0.2 m•kg, 1.4
ft•lb)
Oil filter element drain
bolt: 10 Nm (1.0 m•kg, 7.2
ft•lb)
Crankcase oil drain bolt: 20 Nm (2.0 m•kg, 14
ft•lb)
Oil tank drain bolt: 18 Nm (1.8 m•kg, 13
ft•lb)
Engine guard: 7 Nm (0.7 m•kg, 5.1
ft•lb)
Oil quantity: Periodic oil change:1.1 L (0.97 Imp qt, 1.16
US qt)
With oil filter replace-
ment:
1.2 L (1.06 Imp qt, 1.27
US qt)
Total amount:
1.4 L (1.23 Imp qt, 1.48
US qt)
Bolt (oil tank): 7 Nm (0.7 m•kg, 5.1
ft•lb)
Oil pressure check bolt: 10 Nm (1.0 m•kg, 7.2
ft•lb)

3-14
ENGINE
ADJUSTING THE PILOT SCREW
1. Adjust:• Pilot screw "1"
Adjustment steps:
To optimize the fuel flow at a smaller
throttle opening, each machine's pilot
screw has been individually set at the
factory. Before adjusting the pilot
screw, turn it in fully and count the
number of turns. Record this number
as the factory-set number of turns
out.
a. Turn in the pilot screw until it is
lightly seated.
b. Turn out the pilot screw by the factory-set number of turns.
ADJUSTING THE ENGINE IDLING
SPEED
1. Start the engine and thoroughly warm it up.
2. Adjust: • Engine idling speed
Adjustment steps:
a. Turn the throttle stop screw "1"
until the specified engine idling
speed.
Using a digital engine tachometer for
idle speed adjustment, detect the en-
gine idling speed by bringing the
sensing element "c" of the engine ta-
chometer close to the ignition coil "2".
ADJUSTING THE VALVE
CLEARANCE
• The valve clearance should be ad0justed when the engine is cool
to the touch.
• The piston must be at Top Dead Center (T.D.C.) on compression
stroke to check or adjust the valve
clearance.
1. Remove:
•Seat
•Fuel tankRefer to "REMOVING THE SEAT,
FUEL TANK AND SIDE COV-
ERS" section.
2. Drain:
• CoolantRefer to "CHANGING THE
COOLANT" section.
3. Remove: • Right radiatorRefer to "RADIATOR" section in
the CHAPTER 5.
• Carburetor Refer to "CARBU RETOR" section
in the CHAPTER 5.
• Spark plug
• Upper engine bracket
• Cylinder head cover Refer to "CAMSHAFTS" section
in the CHAPTER 5. 4. Remove:
• Timing mark accessing screw "1"
• Crankshaft end accessing screw "2"
• O-ring
5. Check: • Valve clearanceOut of specification →Adjust.
Checking steps:
a. Turn the crankshaft counterclock-
wise with a wrench.
b. Align the T.D.C. mark "a" on the
rotor with the align mark "b" on the
crankcase cover when piston is at
T.D.C. on compression stroke.
In order to be sure t hat the piston is at
Top Dead Center, the punch mark "c"
on the exhaust camshaft and the
punch mark "d" on the intake cam-
shaft must align with the cylinder
head surface, as shown in the illustra-
tion.
Pilot screw (example):
1-1/2 turns out
(For EUROPE)
To increase idle speed →Turn the
throttle stop screw "1" in "a".
To decrease idle speed →Turn the
throttle stop screw "1" out "b".
Engine idling speed:1,750–1,950 r/min
Valve clearance (cold):
Intake valve:0.10–0.15 mm
(0.0039–0.0059 in)
Exhaust valve: 0.17–0.22 mm
(0.0067–0.0087 in)

3-17
CHASSIS
CLEANING THE SPARK
ARRESTER (For USA)
• Be sure the exhaust pipe and si-lencer are cool before cleaning
the spark arrester.
• Do not start the engine when cleaning the exhaust system.
1. Remove:• Screw (silencer cap) "1"
2. Remove: • Bolt (spark arrester) "1"
3. Remove: • Tail pipe "1"
• Gasket (tail pipe) "2"
• Spark arrester "3"Pull the spark arrester out of the
silencer.
• Gasket (spark arrester) "4"
4. Clean: • Spark arrester
Tap the spark arrester lightly,
then use a wire brush to remove
any carbon deposits.
5. Install: • Gasket (spark arrester)
• Spark arresterInsert the spark arrester into the
silencer and align the bolt holes.
• Gasket (tail pipe)
• Bolt (spark arrester) 6. Install:
• Silencer cap
First tighten the two screws "a" locat-
ed horizontally apart, and then tighten
the others.
CHASSIS
BLEEDING THE HYDRAULIC
BRAKE SYSTEM
Bleed the brake system if:
• The system has been disassem-bled.
• A brake hose has been loosened
or removed.
• The brake fluid is very low.
• The brake operation is faulty.
A dangerous loss of braking per-
formance may occur if the brake
system is not properly bled.
1. Remove: • Brake master cylinder cap
• Diaphragm
• Reservoir float (front brake)
• Protector (rear brake)
2. Bleed: •Brake fluid
Air bleeding steps:
a. Add proper brake fluid to the res- ervoir.
b. Install the diaphragm. Be careful not to spill any fluid or allow the
reservoir to overflow.
c. Connect the clear plastic tube "2" tightly to the caliper bleed screw
"1". A. Front
B. Rear
d. Place the other end of the tube
into a container.
e. Slowly apply the brake lever or pedal several times.
f. Pull the lever in or push down on
the pedal. Hold the lever or pedal
in position.
g. Loosen the bleed screw and allow
the lever or pedal to travel to-
wards its limit.
h. Tighten the bleed screw when the
lever or pedal limit has been
reached; then release the lever or
pedal.
i. Repeat steps (e) to (h) until of the air bubbles have been removed
from the system.
If bleeding is difficult, it may be nec-
essary to let the brake fluid system
stabilize for a few hours. Repeat the
bleeding procedure when the tiny
bubbles in the system have disap-
peared.
j. Add brake fluid to the level line on the reservoir.
Check the operation of the brake
after bleeding the brake system.
3. Install:
• Protector (rear brake)
• Reservoir float (front brake)
• Diaphragm
• Brake master cylinder cap
ADJUSTING THE FRONT BRAKE
1. Check: • Brake lever position "a"
Bolt (spark arrester): 7 Nm (0.7 m•kg, 5.1
ft•lb)
Silencer cap:5 Nm (0.5 m•kg, 3.6
ft•lb)
Bleed screw:
6 Nm (0.6 m•kg, 4.3
ft•lb)
Brake lever position "a":
Standard posi- tion Extent of ad-
justment
95 mm (3.74 in) 76–97 mm
(2.99–3.82 in)

3-24
CHASSIS
Do not force the adjuster past the
minimum or maximum extent of
adjustment. The adjuster may be
damaged.
CHECKING THE TIRE PRESSURE
1. Measure:• Tire pressure
Out of specification →Adjust.
• Check the tire while it is cold.
• Loose bead stoppers allow the tire
to slip off its position on the rim
when the tire pressure is low.
• A tilted tire valve stem indicates that
the tire slips off its position on the
rim.
• If the tire valve st em is found tilted,
the tire is considered to be slipping
off its position. Correct the tire posi-
tion.
CHECKING AND TIGHTENING THE
SPOKES
1. Inspect: • Spokes "1"Bend/damage →Replace.
Loose spoke →Retighten.
2. Tighten: • Spokes
Be sure to retighten these spokes be-
fore and after break-in. After a prac-
tice or a race check spokes for
looseness.
CHECKING THE WHEELS
1. Inspect:
• Wheel runoutElevate the wheel and turn it.
Abnormal runout → Replace.
2. Inspect: • Bearing free playExist play →Replace.
CHECKING AND ADJUSTING THE
STEERING HEAD
1. Elevate the front wheel by placing a suitable stand under the engine.
2. Check: • Steering stemGrasp the bottom of the forks and
gently rock the fork assembly
back and forth.
Free play →Adjust steering head.
3. Check: • Steering smooth actionTurn the handlebar lock to lock.
Unsmooth action →Adjust steer-
ing ring nut. 4. Adjust:
• Steering ring nut
Steering ring nut adjustment
steps:
a. Remove the headlight.
b. Remove the handlebar and upper bracket.
c. Loosen the steering ring nut "1" using the steering nut wrench "2".
d. Tighten the steering ring nut "3" using steering nut wrench "4".
• Apply the lithium soap base grease
on the thread of the steering stem.
• Set the torque wrench to the steer- ing nut wrench so that they form a
right angle.
e. Loosen the steering ring nut one turn.
f. Retighten the steering ring nut us- ing the steering nut wrench.
Avoid over-tightening.
Standard tire pressure:100 kPa (1.0 kgf/cm2,
15 psi)
Spokes: 3 Nm (0.3 m•kg, 2.2
ft•lb)
Steering nut wrench:YU-33975/90890-01403
Steering nut wrench: YU-33975/90890-01403
Steering ring nut (initial
tightening): 38 Nm (3.8 m•kg, 27
ft•lb)
Steering ring nut (final
tightening): 7 Nm (0.7 m•kg, 5.1
ft•lb)

3-27
ELECTRICAL
ELECTRICAL
CHECKING THE SPARK PLUG
1. Remove:• Spark plug
2. Inspect:
• Electrode "1"Wear/damage →Replace.
• Insulator color "2"
Normal condition is a medium to
light tan color.
Distinctly different color →Check
the engine condition.
When the engine runs for many hours
at low speeds, the spark plug insula-
tor will become sooty, even if the en-
gine and carburetor are in good
operating condition.
3. Measure: • Plug gap "a"Use a wire gauge or thickness
gauge.
Out of specification →Regap.
4. Clean the plug with a spark plug cleaner if necessary.
5. Tighten: • Spark plug
• Before installing a spark plug, clean the gasket surface and plug sur-
face.
• Finger-tighten "a" the spark plug before torquing to specification "b".
CHECKING THE IGNITION TIMING
1. Remove:• Timing mark accessing screw "1"
2. Attach: • Timing light
• Inductive tachometerTo the ignition coil lead (orange
lead"1").
3. Adjust: • Engine idling speedRefer to "ADJUSTING THE EN-
GINE IDLING SPEED" section.
4. Check: • Ignition timingVisually check the stationary
pointer "a" is within the firing
range "b" on the rotor.
Incorrect firing range →Check ro-
tor and pickup assembly.
5. Install: • Timing mark accessing screw
CHECKING AND CHARGING THE
BATTERY
Batteries generate explosive hy-
drogen gas and contain electrolyte
which is made of poisonous and
highly caustic sulfuric acid. There-
fore, always follow these preven-
tive measures:
• Wear protective eye gear when handling or working near batter-
ies. • Charge batteries
in a well-venti-
lated area.
• Keep batteries away from fire, sparks or open flames (e.g.,
welding equipment, lighted ciga-
rettes).
• DO NOT SMOKE when charging
or handling batteries.
• KEEP BATTERIES AND ELEC- TROLYTE OUT OF REACH OF
CHILDREN.
• Avoid bodily contact with elec- trolyte as it can cause severe
burns or permanent eye injury.
FIRST AID IN CASE OF BODILY
CONTACT:
EXTERNAL
• Skin — Wash with water.
• Eyes — Flush with water for 15
minutes and get immediate med-
ical attention.
INTERNAL
• Drink large quantities of water or milk followed with milk of magne-
sia, beaten egg or vegetable oil.
Get immediate medical attention.
Charging time, charging amperage
and charging voltage for an MF
battery are different from those of
conventional batteries. The MF
battery should be charged as ex-
plained in the charging method il-
lustrations. If the battery is
overcharged, the electrolyte level
will drop considerably. Therefore,
take special care when charging
the battery.
Since MF batteries are sealed, it is
not possible to check the charge state
of the battery by measuring the spe-
cific gravity of the electrolyte. There-
fore, the charge of the battery has to
be checked by measuring the voltage
at the battery terminals.
1. Remove:• Seat
2. Disconnect:
• Battery leads(from the battery terminals)
First, disconnect the negative bat-
tery lead "1", and then the positive
battery lead "2".
Spark plug gap: 0.7–0.8 mm (0.028–
0.031 in)
Spark plug: 13 Nm (1.3 m•kg, 9.4
ft•lb)
Timing light:
YM-33277-A/90890-
03141