2008 YAMAHA YFZ450 heating

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the transmission.

Always use the clutch when changing gears.
The engine, transmission and drive train are
not designed to withstand the shock of
forced shifting and can be damaged by shift-
ing without using the clutch.
EBU20670
Engine break-in
There is never a more important period in the life of
your engine than the first 20 hours of riding. For
this reason, you should read the following material
carefully.
Since the engine is brand new, do not put an ex-
cessive load on it for the first 20 hours. The various
parts in the engine wear and polish themselves to
the correct operating clearances. During this peri-
od, prolonged full-throttle operation or any condi-
tion that might result in engine overheating must
be avoided.
0–10 hours
Avoid prolonged operation above 1/2 throttle. Vary
the speed of the ATV regularly. Do not operate it at
one set throttle position.
10–20 hours
Avoid prolonged operation above 3/4 throttle. Rev
the engine through the gears freely, but do not use
full throttle at any time.
20 hours and beyond
The ATV can now be operated normally.CAUTION:

ECB00220
If any engine trouble should occur during the
engine break-in period, immediately have a
Yamaha dealer check the ATV.
EBU20721
Parking
When parking the ATV, stop the engine, shift into
first gear, apply the parking brake, and then turn
the fuel cock to “OFF”.

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12. Install the washer onto the air filter element
frame, and then insert the wing bolt into the
hole in the air filter element frame.
CAUTION:

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

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.
CAUTION:

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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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.