2009 YAMAHA YZ450F oil

3-5
PRE-OPERATION INSPECTION AND MAINTENANCE
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 cool-
ing system for leakage.P.3-6 – 7
FuelCheck that a fresh gasoline is filled in the fuel tank. Check the fuel
line for leakage.P.1-8
Engine oilCheck that the oil level is correct. Check the crankcase and oil line
for leakage.P.3-9 – 10
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-7
Throttle grip/HousingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P.3-7 – 8
Brakes Check the play of front brake and effect of front and rear brake. P.3-14 – 16
Drive chainCheck drive chain slack and alignment. Check that the drive chain
is lubricated properly.P.3-17 – 18
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-20 – 21
SteeringCheck that the handlebar can be turned smoothly and have no ex-
cessive play.P.3-21 – 22
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage.
P.3-18 – 20
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 mounted and has no cracks. P.4-3 – 4
Rear wheel sprocket Check that the rear wheel sprocket tightening bolt is not loose. P.3-17
Lubrication Check for smooth operation. Lubricate if necessary. P.3-23
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-11
Lead connectorsCheck that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-3
SettingsIs 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.7-1 – 10

3-6
ENGINE
ENGINE
CHECKING THE COOLANT LEVEL
Do not remove the radiator cap
"1", drain bolt and hoses when the
engine and radiator are hot. Scald-
ing hot fluid and steam may be
blown out under pressure, which
could cause serious injury. When
the engine has cooled, place a
thick towel over the radiator cap,
slowly rotate the cap counter-
clockwise to the detent. This pro-
cedure allows any residual
pressure to escape. When the
hissing sound has stopped, press
down on the cap while turning
counterclockwise and remove it.
Hard water or salt water is harmful
to the engine parts. You may use
distilled water, if you can't get soft
water.
1. Place the machine on a level
place, and hold it in an upright po-
sition.
2. Remove:
• Radiator cap
3. Check:
• Coolant level "a"
Coolant level low→Add coolant.
1. Radiator
CHANGING THE COOLANT
Do not remove the radiator cap
when the engine is hot.
Take care so that coolant does not
splash on painted surfaces. If it
splashes, wash it away with water.
1. Place a container under the en-
gine.
2. Remove:
• Engine guard "1"
• Coolant drain bolt "2"
3. Remove:
•Radiator cap
Drain the coolant completely.
4. Clean:
• Cooling system
Thoroughly flush the cooling sys-
tem with clean tap water.
5. Install:
• Copper washer
• Coolant drain bolt
• Engine guard
• Bolt (engine guard)
6. Fill:
•Radiator
•Engine
To specified level.
• Do not mix more than one type of
ethylene glycol antifreeze con-
taining corrosion inhibitors for
aluminum engine.
• Do not use water containing im-
purities or oil.
Handling notes of coolant:
The coolant is harmful so it should be
handled with special care.
• When coolant splashes to your
eye.
Thoroughly wash your eye with
water and see your doctor.
• When coolant splashes to your
clothes.
Quickly wash it away with water
and then with soap.
• When coolant is swallowed.
Quickly make him vomit and take
him to a doctor.
7. Install:
•Radiator cap
Start the engine and warm it up
for a several minutes.
8. Check:
• Coolant level
Coolant level low→Add coolant.
CHECKING THE RADIATOR CAP
1. Inspect:
• Seal (radiator cap) "1"
• Valve and valve seat "2"
Crack/damage→Replace.
Exist fur deposits "3" →Clean or
replace.
CHECKING THE RADIATOR CAP
OPENING PRESSURE
1. Attach:
• Radiator cap tester "1" and adapt-
er "2"
Coolant drain bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (engine guard):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Recommended coolant:
High quality ethylene
glycol anti-freeze con-
taining anti-corrosion
for aluminum engine
Coolant "1" and water
(soft water) "2" mixing ra-
tio:
50%/50%
Coolant capacity:
0.99 L (0.87 Imp qt, 1.05
US qt)
Radiator cap tester:
YU-24460-01/90890-
01325
Radiator cap tester
adapter:
YU-33984/90890-01352

3-8
ENGINE
d. Tighten the locknut.
Before adjusting the throttle cable
free play, the engine idle speed
should be adjusted.
After adjusting the throttle cable
free play, start the engine and turn
the handlebar to right and left and
make sure that the engine idling
does not run faster.
LUBRICATING THE THROTTLE
1. Remove:
• Cover (throttle cable cap) "1"
• Cover (grip cap) "2"
• Throttle grip cap "3"
2. Apply:
• Lithium soap base grease
On the throttle cable end "a".
3. Install:
• Throttle grip cap
• Screw (throttle grip cap)
• Cover (grip cap)
• Cover (throttle cable cap)ADJUSTING THE HOT STARTER
LEVER FREE PLAY
1. Check:
• Hot starter lever free play "a"
Out of specification→Adjust.
2. Adjust:
• Hot starter lever free play
Hot starter lever free play adjust-
ment steps:
a. Loosen the locknut "1".
b. Turn the adjuster "2" until free
play "a" is within the specified lim-
its.
c. Tighten the locknut.
After adjustment, check proper oper-
ation of hot starter.
CLEANING THE AIR FILTER
ELEMENT
Proper air filter maintenance is the
biggest key to preventing premature
engine wear and damage.
Never run the engine without the
air filter element in place; this
would allow dirt and dust to enter
the engine and cause rapid wear
and possible engine damage.
1. Remove:
•Seat
• Fitting bolt "1"
•Washer "2"
• Air filter element "3"
• Air filter guide "4"2. Clean:
• Air filter element
Clean them with solvent.
After cleaning, remove the remaining
solvent by squeezing the element.
• Do not twist the element when
squeezing the element.
• Leaving too much of solvent in
the element may result in poor
starting.
3. Inspect:
• Air filter element
Damage→Replace.
4. Apply:
• Foam-air-filter oil or equivalent oil
to the element
Squeeze out the excess oil. Element
should be wet but not dripping.
5. Install:
• Air filter guide "1"
Align the projection "a" on filter guide
with the hole "b" in air filter element.
6. Apply:
• Lithium soap base grease
On the matching surface "a" on air
filter element. Locknut:
4 Nm (0.4 m•kg, 2.9
ft•lb)
Screw (throttle grip cap):
4 Nm (0.4 m•kg, 2.9
ft•lb)
Hot starter lever free play
"a":
3–6 mm (0.12–0.24 in)
Locknut:
4 Nm (0.4 m•kg, 2.9
ft•lb)

3-9
ENGINE
7. Install:
• Air filter element "1"
• Washer
• Fitting bolt
Align the projection "a" on filter guide
with the hole "b" in air filter case.
CHECKING THE ENGINE OIL
LEVEL
1. Stand the machine on a level sur-
face.
• When checking the oil level make
sure that the machine is upright.
• Place the machine on a suitable
stand.
Never remove the oil tank cap just
after high speed operation. The
heated oil could spurt out. causing
danger. Wait until the oil cools
down to approximately 70°C
(158°F).
2. Idle the engine more than 3 min-
utes while keeping the machine
upright. Then stop the engine and
inspect the oil level.
3. Remove:
• Oil tank cap 14. Inspect:
• Oil level
Check that the engine oil is above
the level mark "a" and that the oil
does not come out when the
check bolt "1" is removed.
Below the level mark "a"→Add oil
through the filler cap hole until it is
above the level mark "a".
Oil comes out at the check bolt→
Drain the oil until it stops coming
out.
When inspecting the oil level, do not
screw the oil level gauge into the oil
tank. Insert the gauge lightly.
• Engine oil also luburicates the
clatch and the wrong oil types or
additives could cause clatch
slippage. Therefore, do not oils
with a grade of CD "a" or higher
and do not use oils labeled "EN-
ERGY CONSERVING II" "b" .
• Do not allow foreign material to
enter the crankcase.
(For USA and CDN)(Except for USA and CDN)
5. Start the engine and let it warm up
for several minutes.
When the oil tank is empty, never
start the engine.
6. Idle the engine more than 10 sec-
onds while keeping the machine
upright. Then stop the engine and
add the oil to the maximum level.
7. Install:
• Oil tank cap
CHANGING THE ENGINE OIL
1. Start the engine and let it warm up
for several minutes.
2. Stop the engine and place an oil
pan under the drain bolt.
3. Remove:
• Oil tank plug "1"
• Oil filler cap "2"
• Drain bolt (with gasket) "3"
• Oil filter drain bolt (O-ring) "4"
• Drain bolt (with gasket) "5"
Drain the crankcase and oil tank
of its oil. Fitting bolt:
2 Nm (0.2 m•kg, 1.4
ft•lb)
Recommended oil:
Yamalube 4, SAE10W-
40 or SAE20W-50
Yamalube 4-R,
SAE10W-50
API service SG type or
higher, JASO standard
MA
4
Recommended oil:
SAE10W-30, SAE10W-
40, SAE15W-40,
SAE20W-40 or
SAE20W-50
API service SG type or
higher, JASO standard
MA

3-10
ENGINE
4. If the oil filter is to be replaced dur-
ing this oil change, remove the fol-
lowing parts and reinstall them.
Replacement steps:
a. Remove the oil filter element cov-
er "1" and oil filter element "2".
b. Check the O-rings "3", if cracked
or damaged, replace them with a
new one.
c. Install the oil filter element and oil
filter element cover.
5. Install:
• Gaskets
• Oil filter drain bolt
• Drain bolt (right crankcase)
• Drain bolt (left crankcase)6. Fill:
• Engine oil
7. Install:
• Oil filler cap
8. Inspect:
• Engine (for oil leaks)
• Oil level
Refer to "ENGINE OIL LEVEL IN-
SPECTION".
CHECKING THE OIL PRESSURE
1. Check:
• Oil pressure
Checking steps:
a. Slightly loosen the oil pressure
check bolt "1".
b. 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.
c. Check oil passages and oil pump
for damage or leakage.
d. Start the engine after solving the
problem(s) and recheck the oil
pressure.
e. Tighten the oil pressure check
bolt.
ADJUSTING THE PILOT SCREW
1. Adjust:
•Pilot screw "1"
Adjustment steps:
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 number
as the factory-set number of turns
out.
a. Turn in the pilot screw until it is
lightly seated.
b. Turn out the pilot screw by the
factory-set number of turns.
ADJUSTING THE ENGINE IDLING
SPEED
1. Start the engine and thoroughly
warm it up.
2. Adjust:
• Engine idling speed
Adjustment steps:
a. Adjust the pilot screw.
Refer to "ADJUSTING THE PI-
LOT SCREW" section.
b. Turn the throttle stop screw "1"
until the specified engine idling
speed.
Using a digital engine tachometer for
idle speed adjustment, detect the en-
gine idling speed by bringing the
sensing element "c" of the engine ta-
chometer close to the ignition coil "2".
Oil filter element cover:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Oil filter drain bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Drain bolt (right crank-
case):
20 Nm (2.0 m•kg, 14
ft•lb)
Drain bolt (left crank-
case):
20 Nm (2.0 m•kg, 14
ft•lb)
Oil quantity:
Periodic oil change:
0.95 L (0.84 Imp qt,
1.00 US qt)
With oil filter replace-
ment:
1.0 L (0.88 Imp qt, 1.06
US qt)
Total amount:
1.2 L (1.06 Imp qt, 1.27
US qt)
Oil pressure check bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Pilot screw (example):
1-1/2 turns out
Digital tachometer:
YU-39951-B/90890-
06760
To increase idle speed→Turn the
throttle stop screw "1" in "a".
To decrease idle speed→Turn the
throttle stop screw "1" out "b".

3-12
ENGINE
The thickness "a" of each pad is indi-
cated in hundredths of millimeters on
the pad upper surface.
d. Round off the last digit of the in-
stalled pad number to the nearest
increment.
EXAMPLE:
Installed pad number = 148
Rounded off value = 150
Pads can only be selected in 0.05
mm increments.
e. Locate the rounded-off value and
the measured valve clearance in
the chart "PAD SELECTION TA-
BLE". The field where these two
coordinates intersect shows the
new pad number to use.
Use the new pad number only as a
guide when verifying the valve clear-
ance adjustment.
f. Install the new pads "3" and the
valve lifters "4".
• Apply the engine oil on the valve lift-
ers.
• Apply the molybdenum disulfide oil
on the valve stem ends.
• Valve lifter must turn smoothly
when rotated with a finger.
• Be careful to reinstall valve lifters
and pads in their original place.
g. Install the camshafts (exhaust
and intake).
Refer to "CAMSHAFTS" section
in the CHAPTER 4.
Last digit of pad
numberRounded valve
0, 1 or 2 0
4, 5 or 6 5
8 or 9 10

3-17
CHASSIS
CHECKING THE SPROCKET
1. Inspect:
• Sprocket teeth "a"
Excessive wear→Replace.
Replace the drive sprocket, rear
wheel sprocket and drive chain as a
set.
CHECKING THE DRIVE CHAIN
1. Measure:
• Drive chain length (15 links) "a"
Out of specification→Replace.
• While measuring the drive chain
length, push down on the drive
chain to increase its tension.
• Measure the length between drive
chain roller "1" and "16" as shown.
• Perform this measurement at two or
three different places.
2. Remove:
• Master link clip
•Joint "1"
• Drive chain "2"
3. Clean:
• Drive chain
Place it in kerosene, and brush off
as much dirt as possible. Then re-
move the drive chain from the ker-
osene and dry the drive chain.4. Check:
• Drive chain stiffness "a"
Clean and oil the drive chain and
hold as illustrated.
Stiff→Replace the drive chain.
5. Install:
• Drive chain "1"
• Joint "2"
• Master link clip "3"
Be sure to install the master link
clip to the direction as shown.
a. Turning direction
6. Lubricate:
• Drive chain
ADJUSTING THE DRIVE CHAIN
SLACK
1. Elevate the rear wheel by placing
the suitable stand under the en-
gine.
2. Check:
• Drive chain slack "a"
Above the seal guard installation
bolt.
Out of specification→Adjust.
Before checking and/or adjusting, ro-
tate the rear wheel through several
revolutions and check the slack sev-
eral times to find the tightest point.
Check and/or adjust the drive chain
slack with the rear wheel in this "tight
chain" position.
3. Adjust:
• Drive chain slack
Drive chain slack adjustment
steps:
a. Loosen the axle nut "1" and lock-
nuts "2".
b. Adjust the drive chain slack by
turning the adjusters "3".
c. Turn each adjuster exactly the
same amount to maintain correct
axle alignment. (There are marks
"a" on each side of the drive chain
puller alignment.) NOTICE: Im-
proper drive chain slack will
overload the engine aswell as
other vital parts of the motorcy-
cle and can lead to chain slip-
page or breakage. To prevent
this from occurring, keep the
drive chain slack within the
specified limits. Drive chain length (15
links):
: 242.9 mm
(9.563 in)
Drive chain lubricant:
SAE 10W-30 motor oil
or suitable chain lubri-
cants
Drive chain slack:
50–60 mm (2.0–2.4 in)
To tighten→Turn the adjuster "3"
counterclockwise.
To loosen→Turn the adjuster "3"
clockwise and push wheel for-
ward.

3-18
CHASSIS
A. Right
B. Left
Turn the adjuster so that the drive
chain is in line with the sprocket, as
viewed from the rear.
d. Tighten the axle nut while pushing
down the drive chain.
e. Tighten the locknuts.
CHECKING THE FRONT FORK
1. Inspect:
• Front fork smooth action
Operate the front brake and
stroke the front fork.
Unsmooth action/oil leakage→
Repair or replace.
CLEANING THE FRONT FORK OIL
SEAL AND DUST SEAL
1. Remove:
•Protector
• Dust seal "1"
Use a thin screw driver, and be care-
ful not to damage the inner fork tube
and dust seal.
2. Clean:
• Dust seal "a"
•Oil seal "b"
• Clean the dust seal and oil seal af-
ter every run.
• Apply the lithium soap base grease
on the inner tube.
RELIEVING THE FRONT FORK
INTERNAL PRESSURE
If the front fork initial movement feels
stiff during a run, relieve the front fork
internal pressure.
1. Elevate the front wheel by placing
a suitable 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
ADJUSTING THE FRONT FORK
REBOUND DAMPING FORCE
1. Adjust:
• Rebound damping force
By turning the adjuster "1".• STANDARD POSITION:
This is the position which is back
by the specific number of clicks
from the fully turned-in position.
Do not force the adjuster past the
minimum or maximum extent of
adjustment. The adjuster may be
damaged.
Always adjust each front fork to
the same setting. Uneven adjust-
ment can cause poor handling and
loss of stability.
ADJUSTING THE FRONT FORK
COMPRESSION DAMPING FORCE
1. Adjust:
• Compression damping force
By turning the adjuster "1".
• STANDARD POSITION:
This is the position which is back
by the specific number of clicks
from the fully turned-in position. Axle nut:
135 Nm (13.5 m•kg, 98
ft•lb)
Locknut:
19 Nm (1.9 m•kg, 13
ft•lb)
Air bleed screw:
1 Nm (0.1 m•kg, 0.7
ft•lb)
Stiffer "a" →Increase the re-
bound damping force. (Turn
the adjuster "1" in.)
Softer "b" →Decrease the re-
bound damping force. (Turn
the adjuster "1" out.)
Extent of adjustment:
Maximum Minimum
Fully turned in
position20 clicks out
(from maximum
position)
Standard position:
12 clicks out
* 10 clicks out
* Except for USA and CDN
Stiffer "a" →Increase the com-
pression damping force. (Turn
the adjuster "1" in.)
Softer "b" →Decrease the com-
pression damping force. (Turn
the adjuster "1" out.)
Extent of adjustment:
Maximum Minimum
Fully turned in
position20 clicks out
(from maximum
position)