YAMAHA YZ250F 2010 Manual PDF

3-21
CHASSIS
CHECKING AND TIGHTENING THE
SPOKES
The following procedure applies to all
of the spokes.
1. Check:• SpokesBend/damage →Replace.
Loose spoke →Retighten.
Tap the spokes with a screw-
driver.
A tight spoke will emit a clear, ringing
tone; a loose spoke will sound flat.
2. Tighten: • Spokes
(with a spoke nipple wrench "1")
Be sure to retighten these spokes be-
fore and after break-in.
CHECKING THE WHEELS
1. Inspect:• Wheel runout
Elevate the wheel and turn it.
Abnormal runout → Replace. 2. Inspect:
• Bearing free playExist play →Replace.
CHECKING AND ADJUSTING THE
STEERING HEAD
1. Place a stand under the engine to raise the front wheel off the
ground. WARNING! Securely
support the vehicle so that
there is no danger of it falling
over.
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 number plate.
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.
g. Check the steering stem by turn-ing it lock to lock. If there is any
binding, remove the steering stem
assembly and inspect the steer-
ing bearings.
Spoke nipple wrench:
YM-01521/90980-01521
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)

3-22
CHASSIS
h. Install the washer "5", upper bracket "6", steering stem nut "7",
handlebar "8", handlebar upper
holder "9" and number plate "10".
• Apply the lithium soap base grease on the contact surface of the steer-
ing stem nut when installing.
• 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 pro-
jection "c" of the handlebar upper
holder is positioned at the mark on
the handlebar as shown.
• Insert the end of the fuel breather hose "11" into the hole in the steer-
ing stem.
First tighten the bolts on the front
side of the handlebar upper holder,
and then tighten the bolts on the
rear side.
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 brack-
et): 21 Nm (2.1 m•kg, 15
ft•lb)
Number plate: 7 Nm (0.7 m•kg, 5.1
ft•lb)

3-23
CHASSIS
LUBRICATION
To ensure smooth operation of all
components, lubricate your machine
during setup, after break-in, and after
every race.
1. All control cable
2. Clutch lever pivot
3. Shift pedal pivot
4. Footrest pivot
5. Throttle-to-handlebar contact
6. Drive chain
7. Tube guide cable winding por-tion
8. Throttle cable end
9. Clutch cable end
10. Hot starter cable end A. Use Yamaha cable lube or
equivalent on these areas.
B. Use SAE 10W-40 motor oil or
suitable chain lubricants.
C. Lubricate the following areas with high quality, lightweight lith-
ium-soap base grease.
Wipe off any excess grease, and
avoid getting grease on the brake
discs.

3-24
ELECTRICAL
ELECTRICAL
CHECKING THE SPARK PLUG
1. Remove:• Spark plug
2. Inspect:
• Electrode "1"Wear/damage →Replace.
• Insulator color "2"
Normal condition is a medium to
light tan color.
Distinctly different color →Check
the engine condition.
When the engine runs for many hours
at low speeds, the spark plug insula-
tor will become sooty, even if the en-
gine and carburetor are in good
operating condition.
3. Measure: • Plug gap "a"Use a wire gauge or thickness
gauge.
Out of specification →Regap.
4. Clean the plug with a spark plug cleaner if necessary.
5. Tighten: • Spark plug
• Before installing a spark plug, clean the gasket surface and plug sur-
face.
• Finger-tighten "a" the spark plug before torquing to specification "b".
CHECKING THE IGNITION TIMING
1. Remove:• Timing mark accessing screw "1"
2. Attach: • Timing light
• Digital tachometerTo the ignition coil lead (orange
lead"1").
3. Adjust: • Engine idling speedRefer to "ADJUSTING THE EN-
GINE IDLING SPEED" section.
4. Check: • Ignition timingVisually check the stationary
pointer "a" is within the firing
range "b" on the rotor.
Incorrect firing range →Check ro-
tor and pickup assembly.
5. Install: • Timing mark accessing screw
Spark plug gap:
0.7–0.8 mm
(0.028–0.031 in)
Spark plug: 13 Nm (1.3 m•kg, 9.4
ft•lb)
Timing light:
YM-33277-A/90890-
03141

4-1
SEAT, FUEL TANK AND SIDE COVERS
ENGINE
This section is intended for those who have basic knowledge and skill concerning the servicing of Yamaha motorcycles
(e.g., Yamaha dealers, service engineers, etc.) Those who have little knowledge and skill concerning servicing are request-
ed not to undertake inspection, adjustment, disassembly, or reassembly only by reference to this manual. It may lead to
servicing trouble and mechanical damage.
SEAT, FUEL TANK AND SIDE COVERS
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) 1
4 Fitting band 1
5 Fuel tank 1
6 Left side cover 1 Refer to removal section.
7 Right side cover 1 Refer to removal section.
8 Number plate 1 Refer to removal section.
4

4-2
SEAT, FUEL TANK AND SIDE COVERS
REMOVING THE SIDE COVER
1. Remove:• Bolt (side cover)
• Left side cover "1"
• Right side cover "2"
Draw the side cover downward to re-
move it because its claws "a" are in-
serted in the air filter case.
REMOVING THE NUMBER PLATE
1. Remove:• Bolt (number plate)
• Number plate "1"
• The projection "a" is inserted into the band of the number plate. Pull
the band off the projection before
removal.
• Remove the hot starter cable "2" and clutch cable "3" from the cable
guide "b" on the number plate.
• The projection "c" on the lower bracket is inserted into the number
plate. Remove the number plate by
pulling it off the projection.

4-3
EXHAUST PIPE AND SILENCER
EXHAUST PIPE AND SILENCER
REMOVING THE EXHAUST PIPE AND SILENCEROrder Part name Q'ty Remarks A. Except for USA and CDN
Right side cover Refer to "SEAT, FUEL TANK AND SIDE
COVERS" section.
1 Bolt (silencer clamp) 1 Only loosening.
2 Bolt [silencer (front)] 1
3 Bolt [silencer (rear)] 1
4 Silencer 1
5 Silencer clamp 1
6 Nut (exhaust pipe) 2
7 Exhaust pipe 1
8 Gasket 2
9 Wave washer 3

4-4
EXHAUST PIPE AND SILENCER
CHECKING THE SILENCER AND
EXHAUST PIPE
1. Inspect:• Gasket "1"
Damage →Replace.
CHANGING THE SILENCER FIBER
1. Remove: • Rivet (front) "1"
• Inner pipe "2"
Take care not to damage the rivet
fitting holes (ø4. 9 mm) "a" in re-
moval.
Pull out the inner pipe while lightly
tapping the stay "b" on the silencer
using a soft hammer.
2. Replace: • Fiber "1"
3. Install: • Inner pipe "1"
• Rivet (front) "2"
• Apply heat resistant sealant along the plate edge "a" on the inside of
the silencer and also along the si-
lencer edge "b" as shown.
• Take care not to allow the fiber out of place when installing the inner
pipe.
INSTALLING THE SILENCER AND
EXHAUST PIPE
1. Install:
• Gasket
• Exhaust pipe "1"
• Nut (exhaust pipe) "2"
First temporarily tighten both nuts to
13 Nm (1.3 m•kg, 9.4 ft•lb). Then re-
tighten the same nut to 20 Nm (2.0
m•kg, 14 ft•lb).
2. Install:• Silencer clamp "1"
• Gasket "2"
• Silencer "3"
• Washer "4"
• Bolt (silencer) "5"
• Install the gasket with its meshed area "a" toward the exhaust pipe
side.
• The gasket should be installed ac- cording to the dimension shown.
Nut (exhaust pipe): 20 Nm (2.0 m•kg, 14
ft•lb)
Silencer clamp: 14 Nm (1.4 m•kg, 10
ft•lb)
Bolt (silencer): 30 Nm (3.0 m•kg, 22
ft•lb)
New

4-5
RADIATOR
RADIATOR
REMOVING THE RADIATOROrder Part name Q'ty Remarks Drain the coolant. Refer to "CHANGING
THE COOLANT" sec-
tion in the CHAPTER 3.
Seat and fuel tank Refer to "SEAT, FUEL TANK AND SIDE
COVERS" section.
1 Radiator guard 2
2 Radiator hose clamp 10 Only loosening.
3 Clutch cable holder 1
4 Radiator hose 1 1
5 Left radiator 1
6 Radiator hose 4 1
7Pipe 1
8 Radiator hose 5 1
9 Right radiator 1
10 Radiator hose 2 1
11 Radiator hose 3 1
12 Radiator breather hose 1
13 Radiator pipe 1 1
2
4 2
3
13
2
2
2
2
2 11
7
8
2
2
69
2 10
12
1
5
1
T R..20 Nm (2.0 m  kg, 14 ft  Ib)

4-6
RADIATOR
HANDLING NOTE
Do not remove the radiator cap
when the engine and radiator are
hot. Scalding hot fluid and steam
may be blown out under pressure,
which could cause serious injury.
When the engine has cooled, open
the radiator cap by the following
procedure:
Place a thick rag, like a towel, over
the radiator cap, slowly rotate the
cap counterclockwise to the de-
tent. This procedure allows any re-
sidual pressure to escape. When
the hissing sound has stopped,
press down on the cap while turn-
ing counterclockwise and remove
it.
CHECKING THE RADIATOR
1. Inspect:• Radiator core "1"
Obstruction →Blow out with com-
pressed air through rear of the ra-
diator.
Bent fin →Repair/replace.
INSTALLING THE RADIATOR
1. Install: • O-ring "1"
• Radiator pipe 1 "2"
• Bolt (radiator pipe) "3"
Apply the lithium soap base grease
on the O-ring.
2. Install:• Radiator breather hose "1"
• Radiator hose 2 "2"
• Radiator hose 4 "3"
• Pipe "4"
• Radiator hose 5 "5"
• Radiator hose 3 "6"To right radiator "7".
3. Install: • Right radiator "1"
• Bolt (right radiator) "2"
• Radiator hose 5 "3"
Refer to "CABLE ROUTING DIA-
GRAM" section in the CHAPTER
2.
4. Install: • Left radiator "1"
• Bolt (left radiator) "2"
• Radiator hose 1 "3"
Refer to "CABLE ROUTING DIA-
GRAM" section in the CHAPTER
2.
5. Tighten:
• Radiator hose clamp "4" 6. Install:
• Radiator guard "1"
First fit the inner hook portion "a" and
then the outer one "b" onto the radia-
tor.
Bolt (radiator pipe):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (right radiator):10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (left radiator): 10 Nm (1.0 m•kg, 7.2
ft•lb)
Radiator hose 1: 2 Nm (0.2 m•kg, 1.4
ft•lb)
Radiator hose clamp: 2 Nm (0.2 m•kg, 1.4
ft•lb)