2008 YAMAHA WR 250F steering wheel
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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
Page 15 of 224
1-5
SPECIAL TOOLS
Steering nut wrench
YU-33975, 90890-01403 This tool is used when tighten the
steering ring nut to specification.
Damper rod holder
YM-01494, 90890-01494 Use this tool to remove and install
the damper rod.
Fork seal driver
YM-A0948, 90890-01502 This tool is used when install the fork
oil seal.
Sheave holder
YS-1880-A, 90890-01701 This tool is used for when loosening
or tightening the flywheel magneto
securing nut.
Pocket tester
YU-3112-C, 90890-03112 Use this tool to inspect the coil resis-
tance, output voltage and amper-
age.
Timing light
YM-33277-A, 90890-03141 This tool is necessary for checking
ignition timing.
Tool name/Part number How to use Illustration
Page 26 of 224
1-16
TORQUE-CHECK POINTS
TORQUE-CHECK POINTS
Concerning the tightening torque, refer to "TIGHTENING TORQUES" section in the CHAPTER 2.
Frame constructionFrame to rear frame
Combined seat and fuel tank Fuel tank to frame
Exhaust system Silencer to rear frame
Engine mounting Frame to engine
Engine bracket to engine
Engine bracket to frame
Steering Steering stem to handlebar Steering stem to frame
Steering stem to upper bracket
Upper bracket to handlebar
Suspension Front Steering stem to front forkFront fork to upper bracket
Front fork to lower bracket
Rear For link type Assembly of links
Link to frame
Link to rear shock absorber
Link to swingarm
Installation of rear shock absorber Rear shock absorber to frame
Installation of swingarm Tightening of pivot shaft
Wheel Installation of wheel Front Tightening of wheel axle
Tightening of axle holder
Rear Tightening of wheel axle Wheel to rear wheel sprocket
Brake Front Brake caliper to front fork
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to handlebar
Tightening of bleed screw
Tightening of brake hose holder
Rear Brake pedal to frame Brake disc to wheel
Tightening of union bolt
Brake master cylinder to frame
Tightening of bleed screw
Tightening of brake hose holder
Fuel system Fuel tank to fuel cock
Lubrication system Tightening of oil hose clamp
Page 36 of 224
2-9
MAINTENANCE SPECIFICATIONS
CHASSISItem Standard Limit
Steering system: Steering bearing type Taper roller bearing ----
Front suspension: Front fork travel 300 mm (11.8 in) ----
Fork spring free length 460 mm (18.1 in) 455 mm (17.9 in)
Spring rate, STD K = 4.4 N/mm (0.449 kg/mm, 25.1 lb/in)----
Optional spring/spacer Yes----
Oil capacity 648 cm
3 (22.8 lmp oz, 21.9 US oz)----
Oil level 132 mm (5.20 in)----
tube and damper rod fully compressed without
spring.) 95–150 mm (3.74–5.91 in)
----
Oil grade Suspension oil "S1"----
Inner tube outer diamet er 48 mm (1.89 in) ----
Front fork top end 5 mm (0.20 in)----
Rear suspension: USA, CDN AUS, NZ, ZA EUROPE
Shock absorber travel 130 mm (5.12
in) ←←----
Spring free length 260 mm (10.24
in) ←←----
Fitting length 249 mm (9.80
in) 245.0 mm (9.65
in)248.5 mm (9.78
in)----
mm (9.39–
10.18 in) ←←----
Spring rate, STD K = 52.0 N/mm
(5.30 kg/mm,
296.8 lb/in) ←←----
Optional spring Yes←←----
Enclosed gas pressure 1,000 kPa (10
kg/cm
2, 142
psi) ←←----
Swingarm: Swingarm free play limitEnd ---- 1.0 mm (0.04 in)
Wheel: USA, CDN, ZA AUS, NZ, EUROPE
Front wheel type Spoke wheel←----
Rear wheel type Spoke wheel←----
Front rim size/material 21 × 1.60/Aluminum←----
Rear rim size/mater ial 18 × 1.85/Aluminum 18 × 2.15/Aluminum ----
Rim runout limit: Radial --------2.0 mm (0.08
in)
Lateral --------2.0 mm (0.08
in)
Page 40 of 224
2-13
TIGHTENING TORQUES
CHASSIS
△- marked portion shall be checked for torque ti ghtening after break-in or before each race.
△Silencer M8 × 1.25 2 30 3.0 22
Silencer clamp M8 × 1.25 1 16 1.6 11
Spark arrester M5 × 0.8 4 7 0.7 5.1
Silencer cap M5 × 0.8 6 5 0.5 3.6
Air induction pipe M6 × 1.0 1 10 1.0 7.2
Air induction pipe clamp M6 × 1.0 1 4 0.4 2.9
Air cut-off valve assembly and bracket M6 × 1.0 2 10 1.0 7.2
Bracket (air cut-off valve) and frame M6 × 1.0 2 7 0.7 5.1
Crankcase M6 × 1.0 11 12 1.2 8.7
Crankcase bearing stopper M6 × 1.0 11 10 1.0 7.2
Crankcase bearing stopper (crankshaft) M6 × 1.0 4 14 1.4 10
Left crankcase cove r M6 × 1.0 8 10 1.0 7.2
Idle gear cover (starter motor) M6 × 1.0 3 10 1.0 7.2
Idle gear plate M6 × 1.0 2 10 1.0 7.2
Right crankcase cove r M6 × 1.0 6 10 1.0 7.2
Clutch cover M6 × 1.0 7 10 1.0 7.2
Crankcase oil drain bolt M10 × 1.25 1 20 2.0 14
△ Crankshaft end accessing screw M32 × 1.5 1 — — —
△ Timing mark accessing screw M14 × 1.5 1 — — —
Drive chain sprocket cover M6 × 1.0 2 8 0.8 5.8
Kick shaft ratchet wheel guide M6 × 1.0 2 12 1.2 8.7
Kickstarter crank M8 × 1.25 1 33 3.3 24
Primary drive gear M18 × 1.0 1 75 7.5 54
Clutch spring M6 × 1.0 5 10 1.0 7.2
Clutch boss M16 × 1.0 1 60 6.0 43
Clutch cable locknut M8 × 1.25 2 7 0.7 5.1
Push lever shaft M6 × 1.0 1 10 1.0 7.2
Drive sprocket M18 × 1.0 1 75 7.5 54
Drive axle oil seal stopper M6 × 1.0 2 10 1.0 7.2
Segment M8 × 1.25 1 30 3.0 22
Shift guide M6 × 1.0 2 10 1.0 7.2
Stopper lever M6 × 1.0 1 10 1.0 7.2
Shift pedal M6 × 1.0 1 12 1.2 8.7
Part to be tightened
Thread size Q'tyTightening torque
Nm m•kg ft•lb
Part to be tightened Thread size Q'tyTightening torque
Nm m•kg ft•lb
△ Upper bracket and outer tube M8 × 1.25 4 21 2.1 15
△ Lower bracket and outer tube M8 × 1.25 4 21 2.1 15
△ Upper bracket and steeri ng stem M24 × 1.0 1 145 14.5 105
△ Handlebar upper holder and handlebar lower holder M8 × 1.25 4 28 2.8 20
△ Handlebar lower holder and upper bracket M10 × 1.25 2 34 3.4 24
△ Steering stem and steering ring nut M28 × 1.0 1Refer to NOTE.
Page 60 of 224
3-5
PRE-OPERATION INSPECTION AND MAINTENANCE
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation or practice, make sure the machine is in good operating condition.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCEItem RoutinePage
Coolant Check that coolant is filled up to the radiator cap. Check the cool-
ing system for leakage. P.3-9 – 10
Fuel Check that a fresh gasoline is filled in the fuel tank. Check the fuel
line for leakage.
P.1-14
Engine oil Check that the oil level is correct. Check the crankcase and oil line
for leakage. P.3-12 – 14
Gear shifter and clutch Check that gears can be shifted correctly in order and that the
clutch operates smoothly. P.3-10
Throttle grip/Housing Check that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.
P.3-10 – 11
Brakes Check the play of front brake and ef fect of front and rear brake. P.3-17 – 20
Drive chain Check drive chain slack and alignment. Check that the drive chain
is lubricated properly. P.3-20 – 21
Wheels Check for excessive wear and ti
re pressure. Check for loose
spokes and have no excessive play. P.3-24
Steering Check that the handlebar can be turned smoothly and have no ex-
cessive play.
P.3-24 – 25
Front forks and rear shock
absorber Check that they operate smoothly and there is no oil leakage.
P.3-21 – 24
Cables (wires) Check that the clutch and throttle cables move smoothly. Check
that they are not caught when the handlebars are turned or when
the front forks travel up and down. —
Exhaust pipe Check that the exhaust pipe is tightly mount ed and has no cracks. P.3-8 – 9
Rear wheel sprocket Check that the rear wheel sprocket tightening bolt is not loose. P.3-20
Lubrication Check for smooth operation. Lubricate if necessary. P.3-26
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-16
Lead connectors Check that the AC magneto, CDI unit, and ignition coil are con-
nected tightly. P.1-3
Settings Is the machine set suitably for the
condition of the racing course
and weather or by taking into account the results of test runs be-
fore racing? Are inspection and maintenance completely done? P.4-1 – 9
Page 79 of 224
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)