2006 YAMAHA YZ250F oil pressure

SPEC
2 - 3 Transmission:
Primary reduction system Gear
Primary reduction ratio 57/17 (3.353)
Secondary reduction system Chain drive
Secondary reduction ratio 48/13 (3.692) (Except for EUROPE)
49/13 (3.769) (For EUROPE)
Transmission type Constant mesh, 5-speed
Operation Left foot operation
Gear ratio: 1st 30/14 (2.143)
2nd 28/16 (1.750)
3rd 29/20 (1.450)
4th 27/22 (1.227)
5th 25/24 (1.042)
Chassis:
USA, CDNEUROPE
(Except
for F)FAUS, NZ,
ZA
Frame type Semi dou-
ble cradle← ← ←
Caster angle 27.0°27.1°27.3°27.0°
Trail 115.4 mm
(4.54 in)117.7 mm
(4.63 in)119.1 mm
(4.69 in)115.4 mm
(4.54 in)
Tire:
Type With tube
Size (front) 80/100-21 51M (For USA, CDN, ZA, AUS, NZ
and F)
80/100-21 51R (For EUROPE except F)
Size (rear) 100/90-19 57M (For USA, CDN, ZA, AUS, NZ
and F)
100/90-19 NHS (For EUROPE except F)
Tire pressure (front and rear) 100 kPa (1.0 kgf/cm
2, 15 psi)
Brake:
Front brake type Single disc brake
Operation Right hand operation
Rear brake type Single disc brake
Operation Right foot operation
Suspension:
Front suspension Telescopic fork
Rear suspension Swingarm (link type monocross suspension)
Shock absorber:
Front shock absorber Coil spring/oil damper
Rear shock absorber Coil spring/gas, oil damper
Wheel travel:
Front wheel travel 300 mm (11.8 in)
Rear wheel travel 310 mm (12.2 in)
Electrical:
Ignition system CDI magneto
GENERAL SPECIFICATIONS

SPEC
2 - 9 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 size
Width 120.2 mm (4.7 in) ----
Height 240 mm (9.4 in) ----
Thickness 22 mm (0.9 in) ----
Radiator cap opening pressure 110 kPa (1.1 kg/cm
2, 15.6 psi) ----
Radiator capacity (total) 0.60 L (0.53 Imp qt, 0.63 US qt) ----
Water pump
Type Single-suction centrifugal pump ----Item Standard Limit
MAINTENANCE SPECIFICATIONS

SPEC
2 - 12 CHASSIS
Item Standard Limit
Steering system:
Steering bearing type Taper roller bearing ----
Front suspension: USA, CDN,
AUS, NZ, ZAEUROPE
Front fork travel 300 mm (11.8 in)← ----
Fork spring free length 454 mm (17.9 in)← 449 mm (17.7 in)
Spring rate, STD K = 4.3 N/mm
(0.438 kg/mm,
24.5 lb/in)← ----
Optional spring Yes← ----
Oil capacity 522 cm
3
(18.4 Imp oz,
17.6 US oz) 527 cm3
(18.6 Imp oz,
17.8 US oz) ----
Oil grade Suspension oil
“S1”← ----
Inner tube outer diameter 48 mm (1.89 in)← ----
Front fork top end 5 mm (0.20 in)← ----
Rear suspension: USA, CDN,
AUS, NZ, ZAEUROPE
Shock absorber travel 131.5 mm
(5.18 in)← ----
Spring free length Approx. 265 mm
(10.43 in)← ----
Fitting length One I.D. mark
257 mm
(10.12 in)One I.D. mark
258 mm
(10.16 in)----
Two I.D. marks
263 mm
(10.35 in)Two I.D. marks
264 mm
(10.39 in)----
Three I.D. marks
254.5 mm
(10.02 in)Three I.D. marks
255.5 mm
(10.06 in)----
One I.D. mark
245.5 ~ 263.5 mm
(9.67 ~ 10.37 in)←----
Two I.D. marks
251.5 ~ 269.5 mm
(9.90 ~ 10.61 in)←----
Three I.D. marks
243.0 ~ 261.0 mm
(9.57 ~ 10.28 in)←----
Spring rate, STD K = 50.0 N/mm
(5.10 kg/mm,
285.6 lb/in)←----
Optional spring Yes← ----
Enclosed gas pressure 1,000 kPa
(10 kg/cm
2,
142 psi)← ----
MAINTENANCE SPECIFICATIONS

3 - 3
INSP
ADJ
MAINTENANCE INTERVALS
FRONT FORK OIL SEAL AND DUST
SEAL
Clean and lube Lithium base grease
PROTECTOR GUIDE
Replace
REAR SHOCK ABSORBER
(After
rain ride)
Inspect and adjust
Lube
Molybdenum disulfide
grease
Replace spring seat Every one year
Retighten
DRIVE CHAIN GUIDE AND ROLLERS
Inspect
SWINGARM
Molybdenum disulfide
grease
Inspect, lube and retighten
RELAY ARM, CONNECTING ROD
Molybdenum disulfide
grease
Inspect, lube and retighten
STEERING HEAD
Inspect free play and retighten
Clean and lube Lithium base grease
Replace bearing
TIRE, WHEELS
Inspect air pressure, wheel run-out,
tire wear and spoke looseness
Retighten sprocket bolt
Inspect bearings
Replace bearings
Lubricate Lithium base grease
THROTTLE, CONTROL CABLE Yamaha cable lube or
SAE 10W-30 motor oil
Inspect dirt and wear on
the throttle cable on the
carburetor side. Check routing and connection
Lubricate
Inspect and clean (throttle cable)
HOT STARTER, CLUTCH LEVER
Inspect free playItemAfter
break-inEvery
race
Every
third
(or
500 km)Every
fifth
(or
1,000 km)As re-
quiredRemarks

3 - 4
INSP
ADJ
PRE-OPERATION INSPECTION AND MAINTENANCE
EC320000
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
CoolantCheck that coolant is filled up to the radiator cap.
Check the cooling system for leakage.P.3-5 ~ 9
FuelCheck that a fresh gasoline is filled in the fuel tank. Check the
fuel line for leakage.P.1-13
Engine oilCheck that the oil level is correct. Check the crankcase and oil
line for leakage.P.3-13 ~ 17
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-9 ~ 10
Throttle grip/HousingCheck 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 effect of front and rear brake. P.3-23 ~ 29
Drive chainCheck drive chain slack and alignment. Check that the drive
chain is lubricated properly.P.3-30 ~ 32
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-40 ~ 41
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-41 ~ 43
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage. P.3-32 ~ 39
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 pipeCheck that the exhaust pipe is tightly mounted and has no
cracks.P.4-3 ~ 5
Rear wheel sprocket Check that the rear wheel sprocket tightening bolt is not loose. P.3-30
Lubrication Check for smooth operation. Lubricate if necessary. P.3-44
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-18
Lead connectorsCheck that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-6
SettingsIs the machine set suitably for the condition of the racing course
and weather or by taking into account the results of test runs
before racing? Are inspection and maintenance completely
done?P.7-1 ~ 21

3 - 17
INSP
ADJ
OIL PRESSURE INSPECTION
1. Check:
Oil pressure
Checking steps:
Slightly loosen the oil pressure check bolt
1.
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.
Check oil passages and oil pump for dam-
age or leakage.
Start the engine after solving the prob-
lem(s) and recheck the oil pressure.
Tighten the oil pressure check bolt.
T R..
Oil pressure check bolt:
10 Nm (1.0 m  kg, 7.2 ft  lb)
PILOT SCREW ADJUSTMENT
1. Adjust:
Pilot screw 1
* Except for USA and CDNAdjustment steps:
NOTE:
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 num-
ber as the factory-set number of turns out.
Turn in the pilot screw until it is lightly
seated.
Turn out the pilot screw by the factory-set
number of turns.
Pilot screw (example):
2-1/2 turns out
* 2-1/4 turns out
OIL PRESSURE INSPECTION/
PILOT SCREW ADJUSTMENT

3 - 33
INSP
ADJFRONT FORK OIL SEAL AND DUST SEAL CLEANING/
FRONT FORK INTERNAL PRESSURE RELIEVING/
FRONT FORK REBOUND DAMPING FORCE ADJUSTMENT
EC36D001
FRONT FORK OIL SEAL AND DUST SEAL
CLEANING
1. Remove:
Protector
Dust seal 1
NOTE:
Use a thin screw driver, and be careful not to
damage the inner fork tube and dust seal.
2. Clean:
Dust seal a
Oil seal b
NOTE:
Clean the dust seal and oil seal after every
run.
Apply the lithium soap base grease on the
inner tube.
FRONT FORK INTERNAL PRESSURE
RELIEVING
NOTE:
If the front fork initial movement feels stiff dur-
ing a run, relieve the front fork internal pres-
sure.
1. Elevate the front wheel by placing a suit-
able stand under the engine.
2. Remove the air bleed screw 1 and release
the internal pressure from the front fork.
3. Install:
Air bleed screw
EC36H002
FRONT FORK REBOUND DAMPING FORCE
ADJUSTMENT
1. Adjust:
Rebound damping force
By turning the adjuster 1.
Stiffer a → Increase the rebound damp-
ing force. (Turn the adjuster 1 in.)
Softer b → Decrease the rebound damp-
ing force. (Turn the adjuster 1 out.)
T R..1 Nm (0.1 m · kg, 0.7 ft · lb)

4 - 50
ENGCLUTCH
EC4A0000
CLUTCH
Extent of removal:
1 Push rod 1, 2 and push lever shaft removal
2 Push rod 1 disassembly
3 Friction plate and clutch plate removal
4 Primary driven gear removal
Extent of removal Order Part name Q’ty Remarks
CLUTCH REMOVAL
Preparation for removal Drain the engine oil. Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
Brake pedal Refer to “ENGINE REMOVAL” section.
Clutch cable Disconnect at engine side.
1 Clutch cover 1
2 Clutch spring 5
3 Pressure plate 1
4 Push rod 1 1
5 Circlip 1
6 Washer 1
7 Bearing 1
8Ball 1
9 Push rod 2 1
1
4
1
3
2