2006 YAMAHA YZ250F steering

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 - 41
INSP
ADJ
STEERING HEAD INSPECTION AND ADJUSTMENT
2. Inspect:
Bearing free play
Exist play → Replace.
EC36U013
STEERING HEAD INSPECTION AND
ADJUSTMENT
1. Elevate the front wheel by placing a suit-
able stand under the engine.
2. Check:
Steering stem
Grasp the bottom of the forks and gently
rock the fork assembly back and forth.
Free play → Adjust steering head.
3. Check:
Steering smooth action
Turn the handlebar lock to lock.
Unsmooth action → Adjust steering ring
nut.
4. Adjust:
Steering ring nut
Steering ring nut adjustment steps:
Remove the number plate.
Remove the handlebar and upper bracket.
Loosen the steering ring nut 1 using the
steering nut wrench 2.
Steering nut wrench:
YU-33975/90890-01403

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.

3 - 43
INSP
ADJ
T R..
Steering stem nut:
145 Nm (14.5 m  kg, 105 ft  lb)
Handlebar upper holder:
28 Nm (2.8 m  kg, 20 ft  lb)
Pinch bolt (upper bracket):
23 Nm (2.3 m  kg, 17 ft  lb)
Number plate:
7 Nm (0.7 m  kg, 5.1 ft  lb)
STEERING HEAD INSPECTION AND ADJUSTMENT

5 - 49
CHAS
EC560000
STEERING
Extent of removal:
1 Lower bracket removal
2 Bearing removal
Extent of removal Order Part name Q’ty Remarks
STEERING REMOVAL
WARNING
Support the machine securely so
there is no danger of it falling over.
Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section in the CHAPTER 4. Preparation for removal Hold the machine by placing the
suitable stand under the engine.
Number plate
Handlebar
Front fenderRefer to “HANDLEBAR” section.
1 Steering stem nut 1
2 Front fork 2 Refer to “FRONT FORK” section.
3 Upper bracket 1
4 Steering ring nut 1 Use special tool.
Refer to “REMOVAL POINTS”.
5 Lower bracket 1
6 Bearing race cover 1
7 Upper bearing 1
8 Lower bearing 1 Refer to “REMOVAL POINTS”.
9 Bearing race 2 Refer to “REMOVAL POINTS”.
2
1
STEERING

5 - 50
CHAS
EC563000
REMOVAL POINTS
Steering ring nut
1. Remove:
•Steering ring nut 1
Use the steering nut wrench 2.
WARNING
Support the steering stem so that it may
not fall down.
Steering nut wrench:
YU-33975/90890-01403
Lower bearing
1. Remove:
•Lower bearing 1
Use the floor chisel 2.
CAUTION:
Take care not to damage the steering shaft
thread.
Bearing race
1. Remove:
•Bearing race 1
Remove the bearing race using long rod
2 and the hammer.
EC564000
INSPECTION
Steering stem
1. Inspect:
•Steering stem 1
Bend/damage → Replace.
STEERING

5 - 51
CHAS
Bearing and bearing race
1. Wash the bearings and bearing races with
a solvent.
2. Inspect:
•Bearing 1
•Bearing race
Pitting/damage → Replace bearings and
bearing races as a set.
Install the bearing in the bearing races.
Spin the bearings by hand. If the bearings
hang up or are not smooth in their opera-
tion in the bearing races, replace bear-
ings and bearing races as a set.
EC565000
ASSEMBLY AND INSTALLATION
Lower bracket
1. Install:
•Lower bearing 1
NOTE:
Apply the lithium soap base grease on the dust
seal lip and bearing inner circumference.
2. Install:
•Bearing race
•Upper bearing 1
•Bearing race cover 2
NOTE:
Apply the lithium soap base grease on the
bearing and bearing race cover lip.
3. Install:
•Lower bracket 1
NOTE:
Apply the lithium soap base grease on the
bearing, the portion a and thread of the steer-
ing stem.
STEERING

5 - 52
CHASSTEERING
4. Install:
•Steering ring nut 1
Tighten the steering ring nut using the
steering nut wrench 2.
Refer to “STEERING HEAD INSPEC-
TION AND ADJUSTMENT” section in the
CHAPTER 3.
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
5. 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.
6. Install:
•Washer 1
7. Install:
•Front fork 1
•Upper bracket 2
NOTE:
•Temporarily tighten the pinch bolts (lower
bracket).
•Do not tighten the pinch bolts (upper bracket)
yet.
8. Install:
•Washer 1
•Steering stem nut 2
T R..145 Nm (14.5 m · kg, 105 ft · lb)