air filter YAMAHA WR 250F 2008 Owners Manual

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

1-14
STARTING AND BREAK-IN
STARTING AND BREAK-IN
FUEL
Always use the recommended fuel as
stated below. Also, be sure to use
new gasoline the day of a race.
Use only unleaded gasoline. The
use of leaded gasoline will cause
severe damage to the engine inter-
nal parts such as valves, piston
rings, and exhaust system, etc.
If knocking or pinging occurs, use a
different brand of gasoline or higher
octane grade.
• For refueling, be sure to stop the
engine and use enough care not
to spill any fuel. Also be sure to
avoid refueling close to a fire.
• Refuel after the engine, exhaust pipe, etc. have cooled off.
HANDLING NOTE
Never start or run the engine in a
closed area. The exhaust fumes
are poisonous; they can cause
loss of consciousness and death
in a very short time. Always oper-
ate the machine in a well-ventilated
area.
• The carburetor on this machine has a built-in accelerator pump.
Therefore, when starting the en-
gine, do not operate the throttle
or the spark plug will foul.
• Unlike a two-stroke engine, this engine cannot be kick started
when the throttle is open be-
cause the kickstarter may kick
back. Also, if the throttle is open
the air/fuel mixture may be too
lean for the engine to start.
• Before starting the machine, per- form the checks in the pre-opera-
tion check list.
AIR FILTER MAINTENANCE
According to "CLEANING THE AIR
FILTER ELEMENT" section in the
CHAPTER 3, apply the foam-air-filter
oil or its equivalent to the element.
(Excess oil in the element may ad-
versely affect engine starting.)
STARTING A COLD ENGINE
This model is equipped with an igni-
tion circuit cut-off system. The engine
can be started under the following
conditions.
• When the transmission is in neutral.
• When the clutch is disengaged with the transmission in any position.
However, it is recommended to shift
into neutral before starting the en-
gine.
1. Inspect the coolant level.
2. Turn the fuel cock to "ON".
3. Push on the main switch to "ON".
4. Shift the transmission into neutral.
5. Fully open the cold starter knob "1".
6. Start the engine by pushing the start switch or by kicking the kick-
starter crank.
If the engine fails to start by pushing
the start switch, release the switch,
wait a few seconds, and then try
again. Each starting attempt should
be as short as possible to preserve
the battery. Do no t crank the engine
more than 10 seconds on any one at-
tempt. If the engine does not start
with the starter motor, try using the
kickstarter crank.
• If the starter moto r will not turn
when pushing the start switch,
stop pushing it immediately and
kick start the engine in order to
avoid the load on the motor.
• Do not open the throttle while
kicking the kickstarter crank.
Otherwise, the kickstarter crank
may kick back.
7. Return the cold starter knob to its original position and run the en-
gine at 3,000–5,000 r/min for 1 or
2 minutes.
Since this model is equipped with an
accelerator pump, if the engine is
raced (the throttle opened and
closed), the air/fuel mixture will be too
rich and the engine may stall. Also
unlike a two-stroke engine, this model
can idle.
Do not warm up th e engine for ex-
tended periods of time.
STARTING A WARM ENGINE
Do not operate the cold starter knob
and throttle. Pull the hot starter lever
"1" and start the engine by pushing
the start switch or by kicking the kick-
starter crank forcefully with a firm
stroke. As soon as the engine starts,
Release the hot starter lever to close
the air passage.
Restarting an engine after a fall
Pull the hot starter lever and start the
engine. As soon as the engine starts,
Release the hot starter lever to close
the air passage.
Recommended fuel:
Premium unleaded
gasoline only with a re-
search octane number
of 95 or higher.

2-2
GENERAL SPECIFICATIONS
Oil capacity:Engine oilPeriodic oil change 1.1 L (0.97 Imp qt, 1.16 US qt)
With oil filter replacement 1.2 L (1.06 Imp qt, 1.27 US qt)
Total amount 1.4 L (1.23 Imp qt, 1.48 US qt)
Coolant capacity (including all routes): 0.99 L (0.87 Imp qt, 1.05 US qt)
Air filter: Wet type element
Fuel: Type Premium unleaded gasoline only with a research octane
number of 95 or higher.
Tank capacity 8.0 L (1.76 Imp gal, 2.11 US gal)
Reserve 1.1 L (0.24 Imp gal, 0.29 US gal)
Carburetor: Type FCR-MX37
Manufacturer KEIHIN
Spark plug: Type/manufacturer CR9E/NGK (resistance type)
Gap 0.7–0.8 mm (0.028–0.031 in)
Clutch type: Wet, multiple-disc
Transmission: USA, CDN, ZA, AUS, NZEUROPE
Primary reduction system Gear←
Primary reduction ratio 57/17 (3.353)←
Secondary reduction system Chain drive←
Secondary reduction ratio 50/13 (3.846)47/14 (3.357)
Transmission type Constant mesh, 5-speed←
Operation Left foot operation←
Gear ratio: 1st 31/13 (2.385)←
2nd 28/16 (1.750)←
3rd 23/17 (1.353)←
4th 23/21 (1.095)←
5th 17/19 (0.895)←
Chassis: USA, CDN, ZA AUS, NZ EUROPE
Frame type Semi double cra-
dle ←←
Caster angle 27.0 °26.6 °26.5 °
Trail 115 mm (4.53 in) 114 mm (4.49 in) 113 mm (4.45 in)
Tire: Type With tube
Size (front) 80/100-21 51M (For USA, CDN and ZA)
90/90-21 54R (For EUROPE, AUS and NZ)
Size (rear) 100/100-18 59M (For USA, CDN and ZA)
130/90-18 69R (For EUROPE, AUS and NZ)
Tire pressure (front and rear) 100 kPa (1.0 kgf/cm
2, 15 psi)
2

2-8
MAINTENANCE SPECIFICATIONS
Carburetor:USA, CDN, ZA,
AUS, NZ EUROPE
Type/manufacturer FCR-MX37/KEIHIN← ----
I. D. mark 5UME E05UML L0----
Main jet (M.J) #170#160----
Main air jet (M.A.J) #115← ----
Jet needle (J.N) NJRUNNGU----
Cutaway (C.A) 1.5←----
Pilot jet (P.J) #42#45 ----
Pilot air jet (P.A.J) #70← ----
Pilot outlet (P.O) ø0.9←----
Bypass (B.P) ø1.0←----
Valve seat size (V.S) ø3.8←----
Starter jet (G.S) #68← ----
Leak jet (Acc.P) #70← ----
Float height (F.H) 8 mm (0.31 in)← ----
Engine idle speed 1,750–1,950 r/min← ----
Intake vacuum 31.3–36.7 kPa
(235–275 mmHg,
9.25–10.83 inHg) ←
----
Hot starter lever free play 3–6 mm (0.12–0.24
in) ←
----
Lubrication system: Oil filter type Paper type----
Oil pump type Trochoid type----
Tip clearance 0.12 mm or less (0.0047 in or less) 0.20 mm (0.008
in)
Side clearance 0.09–0.17 mm (0.0035–0.0067 in) 0.24 mm (0.009
in)
Housing and rotor clearance 0.03–0.10 mm (0.0012–0.0039 in) 0.17 mm
(0.0067 in)
Cooling: Radiator core sizeWidth 120.2 mm (4.73 in)----
Height 240 mm (9.45 in)----
Thickness 22 mm (0.87 in)----
Radiator cap opening pressure 110 kPa (1.1 kg/cm
2, 15.6 psi)----
Radiator capacity (total) 0.54 L (0.48 Imp qt, 0.57 US qt)----
Water pump Type Single-suction centrifugal pump----
Item
StandardLimit

2-12
TIGHTENING TORQUES
Cylinder head (stud bolt)M8 × 1.25 1 15 1.5 11
Cylinder head (bolt) M9 × 1.25 4 38 3.8 27
Cylinder head (nut) M6 × 1.0 2 10 1.0 7.2
Cylinder head cover M6 × 1.0 2 10 1.0 7.2
Cylinder M6 × 1.0 1 10 1.0 7.2
Balancer weight M6 × 1.0 2 10 1.0 7.2
Balancer shaft driven gear M14 × 1.0 1 50 5.0 36
Timing chain guide (intake side) M6 × 1.0 2 10 1.0 7.2
Timing chain tensioner M6 × 1.0 2 10 1.0 7.2
Timing chain tensioner cap bolt M6 × 1.0 1 7 0.7 5.1
Impeller M8 × 1.25 1 14 1.4 10
Radiator hose clamp M6 × 1.0 10 2 0.2 1.4
Coolant drain bolt M6 × 1.0 1 10 1.0 7.2
Water pump housing M6 × 1.0 4 10 1.0 7.2
Radiator stay M6 × 1.0 6 10 1.0 7.2
Radiator M6 × 1.0 4 10 1.0 7.2
Radiator pipe M6 × 1.0 1 10 1.0 7.2
Oil pump cover M4 × 0.7 1 2 0.2 1.4
Oil pump M6 × 1.0 3 10 1.0 7.2
Oil filter element drain bolt M6 × 1.0 1 10 1.0 7.2
Oil filter element cover M6 × 1.0 2 10 1.0 7.2
Oil strainer (crankcase) M6 × 1.0 2 10 1.0 7.2
Oil delivery pipe 1 (M10) M10 × 1.25 1 20 2.0 14
Oil delivery pipe 1 (M8) M8 × 1.25 2 18 1.8 13
Oil hose M6 × 1.0 2 8 0.8 5.8
△ Oil hose clamp —2 2 0.2 1.4
Oil strainer (oil tank) M6 × 1.0 1 9 0.9 6.5
Oil tank drain bolt M8 × 1.25 1 18 1.8 13
Oil tank (upper) M6 × 1.0 1 7 0.7 5.1
Oil tank and frame M6 × 1.0 3 9 0.9 6.5
Oil pressure check bolt M6 × 1.0 1 10 1.0 7.2
Carburetor joint M6 × 1.0 2 10 1.0 7.2
Carburetor joint clamp M4 × 0.7 2 3 0.3 2.2
Air filter joint clamp M6 × 1.0 1 3 0.3 2.2
Throttle cable adjust bolt and locknut M6 × 0.75 1 4 0.4 2.9
Throttle cable (pull) M6 × 1.0 1 4 0.4 2.9
Throttle cable (return) M12 × 1.0 1 11 1.1 8.0
Throttle cable cover M5 × 0.8 2 4 0.4 2.9
Hot starter plunger M12 × 1.0 1 2 0.2 1.4
Hot starter cable adjust bolt and locknut M6 × 0.75 1 4 0.4 2.9
△ Air filter case M6 × 1.0 2 8 0.8 5.8
Air filter joint and air filter case M5 × 0.8 1 4 0.4 2.9
Exhaust pipe M8 × 1.25 2 20 2.0 14
△ Exhaust pipe protector M6 × 1.0 3 10 1.0 7.2
Part to be tightened
Thread size Q'tyTightening torque
Nm m•kg ft•lb

3-2
MAINTENANCE INTERVALS
CLUTCHInspect and adjust ●● Inspect housing, friction plate, clutch
plate and spring.
Replace ●
TRANSMISSION Inspect ●
Replace bearing ●
SHIFT FORK, SHIFT CAM,
GUIDE BAR Inspect ●Inspect wear.
ROTOR NUT Retighten ●●
MUFFLER Inspect and retighten ●●
Clean ●
Replace ●
CRANK Inspect and clean ●●
CARBURETOR Inspect, adjust and clean ●●
AIR INDUCTION SYSTEM Inspect and clean ●● ●●
SPARK PLUG Inspect and clean ●●
Replace ●
DRIVE CHAIN Use chain lube.
Lubricate, slack, alignment ●● Chain slack: 48–58 mm (1.9–2.3 in)
Replace ●
COOLING SYSTEM Check coolant level and leakage ●●
Check radiator cap operation ●
Replace coolant ●Every two years
Inspect hoses ●
OUTSIDE NUTS AND BOLTS Retighten ●● Refer to "STARTING AND BREAK-
IN" section in the CHAPTER 1.
AIR FILTER Clean and lubricate ●● Use foam air-filter oil or equivalent oil.
Replace ●
OIL FILTER Replace ●●
FRAME Clean and inspect ●●
Item
After
break- in Every
race
Every third
(or 500 km) Every
fifth (or
1,000 km)
As re-
quired Remarks
3

3-6
ENGINE
ENGINE
REMOVING THE SEAT, FUEL TANK AND SIDE COVERS
Order Part name Q'ty Remarks Turn the fuel cock to "OFF".
Disconnect the fuel hose.
1Seat 1
2 Air scoop (left and right) 2
3 Bolt (fuel tank) 2
4 Fuel tank 1
5 Left side cover 1 Open the air filter case cover.
6 Right side cover 1 Refer to removal section.
7 Headlight coupler 1
8 Headlight 1

3-7
ENGINE
REMOVING THE SIDE COVER
1. Remove:• Bolt (side cover)
• Right side cover "1"
Draw the side cover backward to re-
move it because its claw "a" is insert-
ed in the air filter case.

3-11
ENGINE
2. Adjust:• Throttle grip free play
Throttle grip free play adjustment
steps:
a. Slide the adjuster cover.
b. Loosen the locknut "1".
c. Turn the adjuster "2" until the
specified free play is obtained.
d. Tighten the locknut.
Before adjusting the throttle cable
free play, the engine idle speed
should be adjusted.
After adjusting the throttle cable
free play, start the engine and turn
the handlebar to right and left and
make sure that the engine idling
does not run faster.
LUBRICATING THE THROTTLE
1. Remove: • Cover (throttle cable cap) "1"
• Cover (grip cap) "2"
• Throttle grip cap "3"
2. Apply: • Lithium soap base grease
On the throttle cable end "a". 3. Install:
• Throttle grip cap
• Screw (throttle grip cap)
• Cover (grip cap)
• Cover (throttle cable cap)
ADJUSTING THE HOT STARTER
LEVER FREE PLAY
1. Check: • Hot starter lever free play "a"Out of specification →Adjust.
2. Adjust: • Hot starter lever free play
Hot starter lever free play adjust-
ment steps:
a. Loosen the locknut "1".
b. Turn the adjuster "2" until free
play "a" is within the specified lim-
its.
c. Tighten the locknut.
After adjustment, check proper oper-
ation of hot starter.
CLEANING THE AIR FILTER
ELEMENT
Proper air filter maintenance is the
biggest key to preventing premature
engine wear and damage.
Never run the engine without the
air filter element in place; this
would allow dirt and dust to enter
the engine and cause rapid wear
and possible engine damage.
1. Open the air filter case cover "1"
Loosen the quick screw "2" and pull
on it to open the air filter case cover.
2. Unhook: •Binder "1"
3. Remove: • Air filter element "1"
• Air filter guide "2"
4. Clean: • Air filter element
Clean them with solvent.
After cleaning, remo ve the remaining
solvent by squeezing the element.
• Do not twist the element when squeezing the element.
• Leaving too much of solvent in
the element may result in poor
starting.
Locknut: 4 Nm (0.4 m•kg, 2.9
ft•lb)
Screw (throttle grip cap):4 Nm (0.4 m•kg, 2.9
ft•lb)
Hot starter lever free play
"a": 3–6 mm (0.12–0.24 in)
Locknut: 4 Nm (0.4 m•kg, 2.9
ft•lb)

3-12
ENGINE
5. Inspect:• Air filter elementDamage →Replace.
6. Apply:
• Foam-air-filter oil or equivalent oil to the element
• Squeeze out the excess oil. Ele-ment should be wet but not drip-
ping.
• Wipe off the oil left on the element surface using a clean dry cloth. (Ex-
cess oil in the element may ad-
versely affect engine starting.)
7. Install:• Air filter guide "1"
• Align the projection "a" on filter guide with the hole "b" in air filter el-
ement.
• Apply the lithium soap base grease on the matching surface "c" on air
filter element.
8. Install:
• Air filter element "1"
Align the projection "a" on filter guide
with the hole "b" in air filter case.
9. Hook:•Binder "1"
Hook the binder "1" so that it contacts
the filter guide projections "a".
CHECKING THE ENGINE OIL
LEVEL
1. Start the engine, warm it up for several minutes, and then turn off
the engine and wait for five min-
utes.
2. Place the machine on a level
place and hold it up on upright po-
sition by placing the suitable
stand under the engine.
3. Inspect: • Oil levelOil should be up to the full level in
the check window "1".
Level check window is not full. →
Add 0.2 L (0.18 Imp qt, 0.21 US
qt) of oil.
(For USA and CDN)
• Do not add any chemical addi- tives. Engine oil also lubricates
the clutch and additives could
cause clutch slippage.
• Do not allow foreign material to enter the crankcase.
(Except for USA and CDN)
• Do not add any chemical addi-tives or use oils with a grade of
CD "a" or higher.
• Do not use oils labeled "ENERGY CONSERVING II" "b" or higher.
Engine oil also lubricates the
clutch and additives could cause
clutch slippage.
• Do not allow foreign material to enter the crankcase.
4. Install:
• Oil tank cap
5. Start the engine and let it warm up for several minutes.
6. Turn off the engine and inspect the oil level once again.
Wait a few minutes until the oil settles
before inspecting the oil level.
CHANGING THE ENGINE OIL
1. Start the engine and warm it up for several minutes, and then turn
off the engine and wait for five
minute.
2. Place the machine on a level place and hold it on upright posi-
tion by placing the suitable stand
under the engine.
3. Place a suitable container under
the engine.
Recommended oil:Yamalube 4,
SAE10W30 or
SAE20W40
Yamalube 4-R,
SAE10W50
API service SG type or
higher, JASO standard
MA
Recommended oil: SAE10W30,
SAE10W40,
SAE15W40, SAE20W40
or SAE20W50
API service SG type or
higher, JASO standard
MA