2008 YAMAHA YFZ450 radiator

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EBU17680
DESCRIPTION
EBU17690
Left view
EBU17700
Right view
1. Headlights
2. Fuel cock
3. Starter (choke)
4. Throttle stop screw
5. Fuse
6. Tail/brake light
7. Coolant reservoir
8. Shift pedal
9. Engine oil tank
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1. Spark arrester
2. Seat
3. Fuel tank cap
4. Radiator cap
5. Oil filter element
6. Brake pedal1
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EBU19540
Fuel
Make sure that there is sufficient fuel in the tank.
(See page 4-8.)
WARNING

EWB00520

Do not overfill the fuel tank. Fuel expands
when it heats up. If the fuel tank is overfilled,
fuel could spill out due to heat from the en-
gine or the sun.

Be careful not to spill fuel, especially on the
engine or exhaust pipe which can cause a
fire and severe injury. Wipe up any spilled
fuel immediately.

Do not refuel right after the engine has been
running and is still very hot.

Be sure the fuel tank cap is closed securely.
EBU19560
Engine oil
Make sure that the engine oil is at the specified lev-
el. Add oil as necessary.
EBU19630
Coolant
Make sure that the coolant is at the specified level.
Add coolant as necessary. (See page 8-20.)
NOTE:

The coolant level must be checked on a cold en-
gine since the level varies with engine tempera-
ture.
WARNING

EWB00510
Wait for the engine and radiator to cool before
removing the radiator cap. You could be
burned by hot fluid and steam blown out under
pressure. Always put a thick rag over the cap
when opening. Allow any remaining pressure
to escape before completely removing the cap.
EBU19710
Front and rear brakes
Brake lever and brake pedal

Check that there is no free play in the brake le-
ver. If there is free play, have a Yamaha dealer
check the brake system.

Check for correct brake pedal height. (See
page 8-36.) If the pedal height is incorrect, have
a Yamaha dealer adjust it.

Check the operation of the lever and pedal. They
should move smoothly and there should be a
firm feeling when the brakes are applied. If not,

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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.CAUTION:
ECB00400

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 engine may not be sufficiently
cooled and the cooling system will not be
protected 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.
NOTE:

If the engine overheats, see page 8-52 for further
instructions.
EBU23560
To change the coolant
WARNING

EWB01890
Wait for the engine and radiator to cool before
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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removing the radiator cap. You could be
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
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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.CAUTION:
ECB00400

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)
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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 engine may not be sufficiently
cooled and the cooling system will not be
protected 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.
NOTE:

If any leakage is found, have a Yamaha dealer
check the cooling system.
15. Install the panel.
EBU23702
Cleaning the air filter element
The air filter element should be cleaned at the in-
tervals specified in the periodic maintenance andlubrication chart. Clean the air filter element more
frequently if you are riding in unusually wet or dusty
areas.
NOTE:

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. Remove the seat. (See page 4-11.)
2. Remove the air filter case cover by unhooking
the holders.
1. Air filter case check hose
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Engine overheating
WARNING

EWB02290
Wait for the engine and radiator to cool before removing the radiator cap. You could be burned by
hot fluid and steam blown out under pressure. Always put a thick rag over the cap when opening.
Allow any remaining pressure to escape before completely removing the cap.
NOTE:

If coolant is not available, tap water can be temporarily used instead, provided that it is changed to the rec-
ommended coolant as soon as possible.
Wait until the
engine has cooled.
Check the coolant level in the
reservoir and radiator.
The coolant level
is OK.The coolant level is low.
Check the cooling system
for leakage.
Have a Yamaha dealer check
and repair the cooling system.Add coolant. (See NOTE.)
Start the engine. If the engine overheats again, have a
Yamaha dealer check and repair the cooling system.
There is
leakage.
There is
no leakage.

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Engine oil quantity:
Without oil filter element replacement:
1.75 L (1.85 US qt) (1.54 Imp.qt)
Quantity in oil tank:
1.55 L (1.64 US qt) (1.36 Imp.qt)
Quantity in crankcase:
0.20 L (0.21 US qt) (0.18 Imp.qt)
With oil filter element replacement:
1.85 L (1.96 US qt) (1.63 Imp.qt)
Quantity in oil tank:
1.55 L (1.64 US qt) (1.36 Imp.qt)
Quantity in crankcase:
0.30 L (0.32 US qt) (0.26 Imp.qt)
Cooling system:
Coolant reservoir capacity (up to the maximum level mark):
0.29 L (0.31 US qt) (0.26 Imp.qt)
Radiator capacity (including all routes):
1.30 L (1.37 US qt) (1.14 Imp.qt)
Air filter:
Air filter element:
Wet element
Fuel:
Recommended fuel:
Premium unleaded gasoline only
Fuel tank capacity:
10.0 L (2.64 US gal) (2.20 Imp.gal)
Fuel reserve amount:
1.9 L (0.50 US gal) (0.42 Imp.gal)
Carburetor:
Manufacturer:
KEIHINType x quantity:
FCR39H x 1
Spark plug (s):
Manufacturer/model:
NGK/CR8E
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
Clutch:
Clutch type:
Wet, multiple-disc
Transmission:
Primary reduction system:
Spur gear
Primary reduction ratio:
62/22 (2.818)
Secondary reduction system:
Chain drive
Secondary reduction ratio:
38/14 (2.714)
Transmission type:
Constant mesh 5-speed
Operation:
Left foot operation
1st:
29/12 (2.416)
2nd:
27/14 (1.928)
3rd:
25/16 (1.562)
4th:
23/18 (1.277)