light YAMAHA YFZ450 2008 User Guide

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EBU19840
Chassis fasteners
Make sure that all nuts, bolts and screws are prop-
erly tightened.
EBU19850
Instruments, lights and switches
Check that all instruments, lights and switches are
working properly. Correct if necessary.
1. Tire wear limit

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OPERATION
EBU19900
Read the Owner’s Manual carefully before riding
the ATV.
WARNING

EWB00630
Read the Owner’s Manual carefully to become
familiar with all controls in order to help pre-
vent any loss of control, which could cause an
accident or injury. If there is a control or func-
tion you do not understand, ask your Yamaha
dealer.
EBU20101
Starting a cold engine
WARNING

EWB00640
Always make sure all control cables work
smoothly before you begin riding in cold
weather. If the control cables are frozen or do
not work smoothly, you could be unable to
control the ATV, which could lead to an acci-
dent or collision.
CAUTION:

ECB00150
See the “Engine break-in” section on page 6-5
prior to operating the engine for the first time.
1. Set the parking brake.
2. Turn the fuel cock to “ON”.
3. Turn the main switch to “ON” and the engine
stop switch to “RUN”.
4. Shift the transmission into neutral. The neutral
indicator light should come on. If the indicator
light does not come on, have a Yamaha deal-
er check the electrical circuit.
NOTE:

This model is equipped with an ignition circuit cut-
off system. The engine can be started under the
following conditions.

The transmission is in neutral.

The clutch is disengaged with the transmission
in gear. However, it is recommended to shift into
neutral before starting the engine.
5. Use the starter (choke) in reference to the fig-
ure:

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attempt.
7. If the engine is started with the starter (choke)
in position (1), the starter (choke) should be
returned to position (2) to warm up the engine.
If the engine is started with the starter (choke)
in position (2), keep the starter (choke) in this
position to warm up the engine.
CAUTION:

ECB00160
For maximum engine life, always warm the en-
gine up before starting off. Never accelerate
hard when the engine is cold!
8. Continue warming up the engine until it idles
smoothly, then return the starter (choke) to
position (3) before riding.
NOTE:

The engine is warm when it responds normally to
the throttle with the starter (choke) turned off.
EBU20291
Starting a warm engine
Follow the same procedure as for starting a cold
engine, with the exception that the starter (choke)
is not required when the engine is warm. Instead,
start the engine with the throttle slightly open.
EBU20520
Shifting
This ATV has a 5-speed forward transmission. The
transmission allows you to control the amount of
power you have available at a given speed or for
starting, accelerating, climbing hills, etc.
To shift into neutral, return the throttle lever to the
closed position, apply the clutch, and then repeat-
edly depress the shift pedal until it stops.
When it stops, it will be in first gear. Raise the pedal
slightly to reach the neutral position.
EBU20570
To start out and accelerate
1. Release the throttle lever.
1. Shift pedal
2. Neutral position
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used to allow the ATV to make turns quickly and
easily. It is essential that this skill be learned first at
low speed.
WARNING

EWB01570
Always follow proper procedures for turning
as described in this Owner’s Manual. Practice
turning at low speeds before attempting to turn
at faster speeds. Do not turn at speeds too fast
for your skills or the conditions.
As you approach a curve, slow down and begin to
turn the handlebars in the desired direction. As you
do so, put your weight on the footboard to the out-
side of the turn (opposite your desired direction)
and lean your upper body into the turn. Use the
throttle to maintain an even speed through the
turn. This maneuver will let the wheel on the inside
of the turn slip slightly, allowing the ATV to make
the turn properly.This procedure should be practiced at slow speed
many times in a large unpaved area with no obsta-
cles. If an incorrect technique is used, your ATV
may continue to go straight. If the ATV doesn’t
turn, come to a stop and then practice the proce-
dure again. If the riding surface is slippery or loose,
it may help to position more of your weight over the
front wheels by moving forward on the seat.
Once you have learned this technique, you should
be able to perform it at higher speeds or in tighter
1. Lean towards inside of turn.
2. Support your weight on the outer footrest.
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steering when riding on loose surfaces by pointing
the front wheels slightly uphill. When riding on
slopes, be sure not to make sharp turns either up
or down hill.
If your ATV does begin to tip over, gradually steer
in the downhill direction if there are no obstacles in
your path. As you regain proper balance, gradually
steer again in the direction you wish to travel.
WARNING

EWB01631
Never attempt to turn the ATV around on any
hill until you have mastered the turning tech-
nique as described in the Owner’s Manual on
level ground. Be very careful when turning on
any hill. Avoid crossing the side of a steep hill
if possible.
When crossing the side of a hill:

Always follow proper procedures as de-
scribed in the Owner’s Manual.

Avoid hills with excessively slippery or loose
surfaces.

Shift your weight to the uphill side of the
ATV.CROSSING THROUGH SHALLOW WATER
The ATV can be used to cross slow moving, shal-
low water of up to a maximum of 35 cm (14 in) in
depth. Before entering the water, choose your path
carefully. Enter where there is no sharp drop off,
and avoid rocks or other obstacles which may be
slippery or upset the ATV. Drive slowly and care-
fully.WARNING

EWB01640
Never operate this ATV in fast flowing water or

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20 Engine oil

Change.

Check ATV for oil leakage, and correct if neces-
sary.
√ √√√
21Engine oil filter ele-
ment

Clean or replace if necessary.
√√√
22 Cooling system

Check coolant level and ATV for coolant leakage,
and correct if necessary.
√√√√√

Replace coolant. Every 2 years
23
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Moving parts and
cables

Lubricate.
√√√√
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Throttle lever hous-
ing and cable


Check operation and correct if necessary.

Check throttle cable free play and adjust if neces-
sary.

Lubricate throttle lever housing and cable.
√√√√√
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Front and rear brake
switches

Check operation and correct if necessary.
√√√√√
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Lights and switches

Check operation and correct if necessary.

Adjust headlight beams.
√√√√√
NO. ITEMCHECK OR MAINTENANCE
JOBINITIAL EVERY
Whichev-
er comes
firstmonth 1 3 6 6 12
km
(mi)320
(200)1300
(800)2500
(1600)2500
(1600)5000
(3200)
hours 20 80 160 160 320

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dance with the periodic maintenance and lubrica-
tion chart. In addition, the condition of the spark
plug can reveal the condition of the engine.
To remove the spark plug
1. Remove the seat. (See page 4-11.)
2. Remove the bolts and the quick fastener
screws shown.
3. Remove the fuel tank cap by turning it coun-
terclockwise.
WARNING
EWB01870

Always turn off the engine before removing
the fuel tank cap.

Do not remove the fuel tank cap immediately
after the engine has been running and is still
very hot.

Do not spill gasoline on the engine, exhaust
pipe or muffler.

Never remove the fuel tank cap while smok-
ing, or in the vicinity of sparks, open flames,
or other sources of ignition such as the pilot
lights of water heaters and clothes dryers.
4. Pull the panel backward, and then remove the
panel.
5. Install the fuel tank cap by turning it clockwise.
6. Remove the bolt, lift the rear of the fuel tank,
and then tilt it back.
1. Panel
2. Bolt
3. Quick fastener screw
4. Fuel tank cap
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kit.
To check the spark plug
1. Check that the porcelain insulator around the
center electrode of the spark plug is a medi-
um-to-light tan (the ideal color when the ATV
is ridden normally).
NOTE:

If the spark plug shows a distinctly different color,
the engine could be operating improperly. Do not
attempt to diagnose such problems yourself. In-
stead, have a Yamaha dealer check the ATV.
2. Check the spark plug for electrode erosionand excessive carbon or other deposits, and
replace it if necessary.
To install the spark plug
1. Measure the spark plug gap with a wire thick-
ness gauge and, if necessary, adjust the gap
to specification.
1. Spark plug wrench
1

Specified spark plug:
NGK/CR8E
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
1. Spark plug gap

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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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EBU24740
Brake light switches
The operation of the brake light switches must be
checked and, if necessary, adjusted at the inter-
vals specified in the periodic maintenance and lu-
brication chart.
The brake light switch for the brake pedal can be
adjusted as follows, but the other brake light
switches should be adjusted by a Yamaha dealer.
NOTE:

The brake light switch is properly adjusted when
the brake light comes on just before braking takes
effect.
Turn the adjusting nut while holding the brake light
switch in place. To make the brake light come on
earlier, turn the adjusting nut in direction (a). To
make the brake light come on later, turn the adjust-
ing nut in direction (b).
EBU24820
Adjusting the clutch lever free play
The clutch lever free play must be checked and, if
necessary, adjusted at the intervals specified in
the periodic maintenance and lubrication chart.
The clutch lever free play should measure 8.0–
13.0 mm (0.31–0.51 in) as shown. If the free play
is incorrect, adjust it as follows.
1. Brake light switch
2. Brake light switch adjusting nut
(a)
(b)1
2