YAMAHA YFZ450 2009 Owners Manual

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3. If the coolant is at or below the minimum level
mark, remove panel A. (See page 8-9.)
4. Remove the reservoir cap, add coolant or dis-
tilled water to the maximum level mark, install
the reservoir cap, and then install the panel.NOTICE

ECB00401

If coolant is not available, use distilled water
or soft tap water instead. Do not use hard wa-
ter or salt water since it is harmful to the en-
gine.

If water has been used instead of coolant, re-
place it with coolant as soon as possible,
otherwise the cooling system will not be pro-
tected against frost and corrosion.

If water has been added to the coolant, have
a Yamaha dealer check the antifreeze con-
tent of the coolant as soon as possible, oth-
erwise the effectiveness of the coolant will
be reduced.
TIP

If the engine overheats, see page 8-55 for further
instructions.
EBU23561
To change the coolant
WARNING

EWB01890
Wait for the engine and radiator to cool before
removing the radiator cap. You could be
1. Maximum level mark
2. Minimum level mark
3. Coolant reservoir
4. Coolant reservoir cap
Coolant reservoir capacity (up to the maximum
level mark):
0.29 L (0.31 US qt, 0.26 Imp.qt)
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burned by hot fluid and steam blown out under
pressure. Always place a thick rag over the cap
when opening. Allow any remaining pressure
to escape before completely removing the cap.
1. Place the ATV on a level surface.
2. Remove panel A. (See page 8-9.)
3. Place a container under the engine, and then
remove the coolant drain bolt. (Use a trough
or a similar object as shown.)
4. Remove the radiator cap.5. Remove the coolant reservoir by removing the
bolts.
6. Remove the coolant reservoir cap, and then
turn the coolant reservoir upside down to
empty it.
1. Coolant drain bolt
2. Trough
2 1

1. Radiator cap
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7. After draining the coolant, thoroughly flush the
cooling system with clean tap water.
8. Install the coolant reservoir by installing the
bolts.
9. Replace the coolant drain bolt washer if it is
damaged, install the coolant drain bolt, and
then tighten it to the specified torque.10. Pour the recommended coolant into the reser-
voir to the maximum level mark, and then in-
stall the reservoir cap.
11. Pour the recommended coolant into the radia-
tor until it is full.NOTICE

ECB00401

If coolant is not available, use distilled water
or soft tap water instead. Do not use hard wa-
ter or salt water since it is harmful to the en-
gine.

If water has been used instead of coolant, re-
place it with coolant as soon as possible,
1. Coolant reservoir cap
2. Coolant reservoir
3. Bolt
Tightening torque:
Coolant drain bolt:
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
1 3
2

Antifreeze/water mixture ratio:
1:1
Recommended antifreeze:
High-quality ethylene glycol antifreeze con-
taining corrosion inhibitors for aluminum en-
gines
Coolant quantity:
Radiator capacity (including all routes):
1.30 L (1.37 US qt, 1.14 Imp.qt)
Coolant reservoir capacity (up to the maxi-
mum level mark):
0.29 L (0.31 US qt, 0.26 Imp.qt)

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otherwise the cooling system will not be pro-
tected against frost and corrosion.

If water has been added to the coolant, have
a Yamaha dealer check the antifreeze con-
tent of the coolant as soon as possible, oth-
erwise the effectiveness of the coolant will
be reduced.
12. Install the radiator cap, start the engine, let it
idle for several minutes, and then turn it off.
13. Remove the radiator cap to check the coolant
level in the radiator. If it is low, add sufficient
coolant until it reaches the top of the radiator,
and then install the radiator cap.
14. Start the engine, and then check for coolant
leakage.
TIP

If any leakage is found, have a Yamaha dealer
check the cooling system.
15. Install the panel.
EBU23703
Cleaning the air filter element
The air filter element should be cleaned at the in-
tervals specified in the periodic maintenance and
lubrication chart. Clean the air filter element morefrequently if you are riding in unusually wet or dusty
areas.
TIP

There is a check hose at the bottom of the air filter
case. If dust or water collects in this hose, empty
the hose and clean the air filter element and air fil-
ter case.
1. Place the ATV on a level surface.
2. Remove the seat. (See page 4-11.)
3. Remove the air filter case cover by unhooking
the holders.
1. Air filter case check hose
1

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4. Loosen the wing bolt.
5. Remove the air filter element together with the
wing bolt and washer.6. Remove the wing bolt and washer from the air
filter element.
7. Remove the sponge material from the air filter
element frame.
1. Air filter case cover
2. Air filter case holder
2 1

1. Wing bolt
2. Sponge material
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8. Wash the sponge material gently but thor-
oughly in solvent.
WARNING

EWB01940
Always use parts cleaning solvent to clean the
sponge material. Never use low-flash-point
solvents or gasoline to clean the sponge mate-
rial because the engine could catch fire or ex-
plode.
9. Squeeze the excess solvent out of the sponge
material and let it dry.
NOTICE

ECB00440
Do not twist the sponge material when squeez-
ing it.
10. Check the sponge material and replace it if
damaged.
11. Apply a quality foam air filter oil to the sponge
material.
TIP

The sponge material should be wet but not drip-
ping.
12. Pull the sponge material over the air filter ele-
ment frame.
1. Sponge material
2. Air filter element frame
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13. Install the washer onto the air filter element
frame, and then insert the wing bolt into the
hole in the air filter element frame.
NOTICE

ECB00451
Be sure to install the washer with the bent edge
facing outward as shown.
14. Insert the air filter element into the air filter
case, and then tighten the wing bolt.
15. Install the air filter case cover by hooking the
holders onto the air filter case.
16. Install the seat.
TIP

The air filter element should be cleaned every 20–
40 hours. It should be cleaned and lubricated more
often if the ATV is operated in extremely dusty ar-
eas. Each time the air filter element maintenance
is performed, check the air inlet of the air filter case
for obstructions. Check the air filter case rubber
joint to the carburetor fittings and the rubber joint
manifold fittings for an air-tight seal. Tighten all fit-
tings securely to avoid the possibility of unfiltered
air entering the engine.
NOTICE

ECB00460

Make sure that the air filter element is prop-
erly seated in the air filter case.

Never operate the engine with the air filter el-
ement removed. This will allow unfiltered air
to enter the engine, causing rapid engine
wear and possible engine damage. Addition-
ally, operation without the air filter element
will affect carburetor jetting with subsequent
poor performance and possible engine over-
heating.
1. Washer
1

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EBU27701
Cleaning the spark arrester
Select a well-ventilated area free of combustible
materials and make sure the exhaust and muffler
are cool.
1. Remove the bolt.
2. Remove the tailpipe by pulling it out of the
muffler.
3. Tap the tailpipe lightly, and then use a wire
brush to remove any carbon deposits from the
spark arrester portion of the tailpipe and inside
of the tailpipe housing.4. Insert the tailpipe into the muffler and align the
bolt holes.
5. Install the bolt and tighten it to the specified
torque.
6. Remove the purging bolt.
1. Bolt
1

1. Tailpipe
2. Spark arrester
Tightening torque:
Tailpipe bolt:
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
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7. Start the engine and rev it up approximately
twenty times while momentarily creating ex-
haust system back pressure by blocking the
end of the muffler with a shop towel.
8. Stop the engine and allow the exhaust pipe to
cool.
9. Install the purging bolt and tighten it to the
specified torque.WARNING
EWB02380
Never run the engine in an enclosed area when
purging the spark arrester, otherwise it could
cause injury to the eyes, burns, carbon monox-
ide poisoning, possibly leading to death, and
start a fire.

Always let the exhaust system cool prior to
touching exhaust components.

Always wear eye protection, and make sure
no one is behind the ATV.

Make sure there are no combustible materi-
als in the area.
EBU23940
Adjusting the carburetor
The carburetor should be checked and, if neces-
sary, adjusted at the intervals specified in the peri-
odic maintenance and lubrication chart. The
carburetor is an important part of the engine and
requires very sophisticated adjustment. Therefore,
most carburetor adjustments should be left to a
Yamaha dealer, who has the necessary profes-
sional knowledge and experience. The adjustment
described in the following section, however, may
be performed by the owner as part of routine main-
1. Purging bolt
2. Gasket
Tightening torque:
Purging bolt:
27 Nm (2.7 m·kgf, 20 ft·lbf)
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tenance.
NOTICE

ECB00480
The carburetor has been set and extensively
tested at the Yamaha factory. Changing these
settings without sufficient technical knowl-
edge may result in poor performance of or
damage to the engine.
EBU24030
Checking the engine idling speed
A special tester is needed to check the engine
idling speed on this model.
Therefore, take the ATV to a Yamaha dealer to
have the engine idling speed checked and adjust-
ed.
EBU24044
Adjusting the throttle cable free play
The throttle cable free play should be checked
and, if necessary, adjusted at the intervals speci-
fied in the periodic maintenance and lubrication
chart.
The throttle cable free play should measure 2.0–4.0 mm (0.08–0.16 in) at the throttle lever. Period-
ically check the throttle cable free play and, if nec-
essary, adjust it as follows.
TIP

The engine idling speed must be checked, and ad-
justed if necessary, before adjusting the throttle ca-
ble free play.
1. Loosen the locknut.
2. To increase the throttle cable free play, turn
the throttle cable free play adjusting bolt in di-
rection (a). To decrease the throttle cable free
play, turn the adjusting bolt in direction (b).
Engine idling speed:
1750–1850 r/min