2006 YAMAHA YZ250F fuel

SPEC
2 - 15
NOTE:
- marked portion shall be checked for torque tightening after break-in or before each race.Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Nipple (spoke)—72 3 0.3 2.2
Rear wheel sprocket M8 × 1.25 6 42 4.2 30
Rear brake disc cover M6 × 1.0 2 10 1.0 7.2
Rear brake caliper protector M6 × 1.0 2 7 0.7 5.1
Drive chain puller adjust bolt and locknut M8 × 1.25 2 16 1.6 11
Engine mounting:
Engine and engine bracket (front) M10 × 1.25 1 53 5.3 38
Engine and frame (lower) M10 × 1.25 1 53 5.3 38
Upper engine bracket and frame M10 × 1.25 4 55 5.5 40
Lower engine bracket and frame M8 × 1.25 4 38 3.8 27
Engine and engine bracket (upper) M10 × 1.25 1 55 5.5 40
Lower engine guard M6 × 1.0 3 10 1.0 7.2
Right engine guard M6 × 1.0 1 10 1.0 7.2
CDI unit bracket M6 × 1.0 2 7 0.7 5.1
Cable guide and CDI unit bracket M5 × 0.8 2 4 0.4 2.9
Cable guide and frame M5 × 0.8 1 5 0.5 3.6
Pivot shaft and nut M16 × 1.5 1 85 8.5 61
Relay arm and swingarm M14 × 1.5 1 70 7.0 50
Relay arm and connecting rod M14 × 1.5 1 80 8.0 58
Connecting rod and frame M14 × 1.5 1 80 8.0 58
Rear shock absorber and frame M10 × 1.25 1 56 5.6 40
Rear shock absorber and relay arm M10 × 1.25 1 53 5.3 38
Rear frame (upper) M8 × 1.25 1 32 3.2 23
Rear frame (lower) M8 × 1.25 2 32 3.2 23
Swingarm and brake hose holder M5 × 0.8 4 2 0.2 1.4
Swingarm and patch M4 × 0.7 4 2 0.2 1.4
Upper drive chain tensioner M8 × 1.25 1 16 1.6 11
Lower drive chain tensioner M8 × 1.25 1 16 1.6 11
Drive chain support M6 × 1.0 3 7 0.7 5.1
Seal guard and swingarm M5 × 0.8 4 6 0.6 4.3
Fuel tank mounting boss and frame M10 × 1.25 1 20 2.0 14
Fuel tank M6 × 1.0 2 10 1.0 7.2
Fuel cock M6 × 1.0 2 6 0.6 4.3
Seat set bracket and fuel tank M6 × 1.0 1 7 0.7 5.1
Fuel tank bracket and fuel tank M6 × 1.0 4 7 0.7 5.1
Air scoop and fuel tank M6 × 1.0 6 7 0.7 5.1
Air scoop and radiator guard (lower) M6 × 1.0 2 7 0.7 5.1
Front fender M6 × 1.0 4 7 0.7 5.1
Rear fender (front) M6 × 1.0 2 7 0.7 5.1
Rear fender (rear) M6 × 1.0 2 16 1.6 11
Side cover M6 × 1.0 2 7 0.7 5.1
Seat M8 × 1.25 2 23 2.3 17
Number plate M6 × 1.0 1 7 0.7 5.1
MAINTENANCE SPECIFICATIONS

2 - 18
SPECCABLE ROUTING DIAGRAM
EC240000
CABLE ROUTING DIAGRAM
1Fuel tank breather hose
2Radiator hose 1
3Cylinder head breather hose
4Radiator hose 4
5Clutch cable
6Throttle position sensor lead
7Fuel hose
8Hot starter cable
9Carburetor breather hose
0Carburetor overflow hose
AConnector coverÈInsert the end of the fuel tank
breather hose into the hole in
the steering stem.
ÉPass the cylinder head
breather hose on the outside of
the radiator hose 1 and on the
inside of the radiator pipe (radi-
ator hose 4).
ÊPass the clutch cable through
the cable guides.
ËPass the clutch cable in front of
the radiator mounting boss.ÌPass the fuel hose between the
hot starter cable and throttle
position sensor lead.
ÍPass the carburetor breather
hoses and overflow hose so
that all there hoses do not con-
tact the rear shock absorber.
ÎInstall the connector cover so
that it does not come in
between the radiator hose 1
and radiator.
B A
99
0
Í
B
A
8
3A2Î
7
Ì
ËÉ
1
È
6
5
4
Ê

3 - 2
INSP
ADJ
MAINTENANCE INTERVALS
SHIFT FORK, SHIFT CAM, GUIDE BAR
InspectInspect wear
ROTOR NUT
Retighten
EXHAUST PIPE, SILENCER, PRO-
TECTOR
Inspect and retighten
Clean
Replace * Whichever comes first
CRANK
Inspect and clean
CARBURETOR
Inspect, adjust and clean
SPARK PLUG
Inspect and clean
Replace
DRIVE CHAIN
Use chain lube
Chain slack: 48 ~ 58 mm
(1.9 ~ 2.3 in) Lubricate, slack, alignment
Replace
COOLING SYSTEM
Check coolant level and leakage
Check radiator cap operation
Replace coolant Every two years
Inspect hoses
OUTSIDE NUTS AND BOLTS Refer to “STARTING
AND BREAK-IN” section
in the CHAPTER 1. Retighten
AIR FILTER
Clean and lubricate
Use foam air-filter oil or
equivalent oil
Replace
OIL FILTER
Replace
OIL STRAINER
Clean
FRAME
Clean and inspect
FUEL TANK, COCK
Clean and inspect
BRAKES
Adjust lever position and pedal height
Lubricate pivot point
Check brake disc surface
Check fluid level and leakage
Retighten brake disc bolts, caliper
bolts, master cylinder bolts and union
bolts
Replace pads
Replace brake fluid Every one year
FRONT FORKS
Inspect and adjust
Replace oil Suspension oil “S1”
Replace oil sealItemAfter
break-inEvery
race
Every
third
(or
500 km)Every
fifth
(or
1,000 km)As re-
quiredRemarks


3

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 - 18
INSP
ADJ
ENGINE IDLING SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it up.
2. Adjust:
Engine idling speed
Adjustment steps:
Adjust the pilot screw.
Refer to “PILOT SCREW ADJUSTMENT”
section.
Turn the throttle stop screw 1 until the
specified engine idling speed.
NOTE:
Using a digital engine tachometer for idle
speed adjustment, detect the engine idling
speed by bringing the sensing element c of
the engine tachometer close to the ignition
coil 2.
To increase idle speed → Turn the throt-
tle stop screw 1 in a.
To decrease idle speed → Turn the throt-
tle stop screw 1 out b.
Engine idling speed:
1,900 ~ 2,100 r/min
c2
VALVE CLEARANCE INSPECTION AND
ADJUSTMENT
NOTE:
The valve clearance should be adjusted
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 tank
Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section in the CHAPTER 4.
ENGINE IDLING SPEED ADJUSTMENT/
VALVE CLEARANCE INSPECTION AND ADJUSTMENT

3 - 42
INSP
ADJ
STEERING HEAD INSPECTION AND ADJUSTMENT
Tighten the steering ring nut 3 using
steering nut wrench 4.
NOTE:
Apply the lithium soap base grease on the
thread of the steering stem.
Set the torque wrench to the steering nut
wrench so that they form a right angle.
Steering nut wrench:
YU-33975/90890-01403
T R..
Steering ring nut (initial tightening):
38 Nm (3.8 m  kg, 27 ft  lb)
Loosen the steering ring nut one turn.
Retighten the steering ring nut using the
steering nut wrench.
WARNING
Avoid over-tightening.
T R..
Steering ring nut (final tightening):
7 Nm (0.7 m  kg, 5.1 ft  lb)
Check the steering stem by turning it lock
to lock. If there is any binding, remove the
steering stem assembly and inspect the
steering bearings.
Install the washer 5, upper bracket 6,
washer 7, steering stem nut 8, handle-
bar 9, handlebar upper holder 0 and
number plate A.
NOTE:
The handlebar upper holder should be
installed with the punched mark a forward.
Install the handlebar so that the marks b
are in place on both sides.
Install the handlebar so that the projection
c of the handlebar upper holder is posi-
tioned at the mark on the handlebar as
shown.
Insert the end of fuel breather hose B into
the hole in the steering stem.
CAUTION:
First tighten the bolts on the front side of
the handlebar upper holder, and then
tighten the bolts on the rear side.

4 - 1
ENG
EC400000
ENGINE
SEAT, FUEL TANK AND SIDE COVERS
Extent of removal:
1 Seat removal
2 Fuel tank removal
3 Side covers removal
4 Number plate removal
Extent of removal Order Part name Q’ty Remarks
SEAT, FUEL TANK AND SIDE
COVERS REMOVAL
Preparation for removal 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
Refer to “REMOVAL POINTS”. 6 Right side cover 1
7 Number plate 1
4
2
1
3
3
SEAT, FUEL TANK AND SIDE COVERS
4