light YAMAHA YFZ450 2012 User Guide

5-7
5
Aftermarket tires and rims
The tires and rims that came with your ATV were
designed to match the performance capabilities
and to provide the best combination of handling,
braking, and comfort. Other tires, rims, sizes, and
combinations may not be appropriate.
EBU19840Chassis fasteners Make sure that all nuts, bolts and screws are prop-
erly tightened.
EBU19850Instruments, lights and switches Check that all instruments, lights and switches are
working properly. Correct if necessary.
Fro nt:
Manufacturer/model:DUNLOP/KT851B Bias
Size: AT21 x 7-10
Ty p e : Tu b e l e s s
Rear: Manufacturer/model:DUNLOP/KT355A Radial
Size: AT20 x 10R9
Ty p e : Tu b e l e s s
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EBU19881
OPERATION
EBU19901Read the Owner’s Manual carefully before riding
the ATV. If there is a control or function you do not
understand, ask your Yamaha dealer.
WARNING
EWB00631Read 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.EBU20184Starting a cold engine NOTICEECB00150See 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 key to “ON ” and the engine stop
switch to “”. 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.
TIPThis 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:
Position (1):
Cold engine start with ambient temperature
below 5 ° C (40 °F).
Position (2):
Cold engine start with ambient temperature
between 0 ° C (30 °F) and 30 ° C (90 °F).
Position (3):
Cold engine start with ambient temperature
above 25 °C (80 °F).
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6
EBU20291Starting 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.EBU20522Shifting 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, release the throttle lever, ap-
ply the clutch, and then repeatedly 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, and then re-
lease the clutch.
EBU20592To start out and accelerate1. Release the throttle lever, apply the front or rear brake, and then release the parking
brake.NOTICEECB00200Always close the throttle before shifting gears,
otherwise damage to the engine and drive train
may result.2. Pull the clutch lever to disengage the clutch.1. Shift pedal
2. Neutral position
1
2
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7-12
7
trol.
[EWB02631]

NOTICE: Do not shift gears without
releasing the throttle. Damage to the engine or
drive train may occur.
[ECB01071]
Use this same procedure as you move into the
higher gears. Be sure to coordinate the use of the
throttle and shift pedal properly.
Avoid higher speeds until you are thoroughly famil-
iar with the operation of your ATV.
When slowing down or stopping, release the throt-
tle and apply the brakes smoothly and evenly. As
you slow down, shift to a lower gear. Be sure that
the engine has sufficiently slowed before engaging
a lower gear. Improper use of the brakes or shifting
can cause the tires to lose traction, reducing con-
trol and increasing the possibility of an accident.
TURNING YOUR ATV
WARNING
EWB01771Always 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. ATV could go
out of control, causing a collision or overturn.
To achieve maximum traction on unpaved surfac-
es, the two rear wheels turn together at the same
speed. Therefore, unless the wheel on the inside
of the turn is allowed to slip or lose some traction,
the ATV will resist turning. A special turning tech-
nique must be used to allow the ATV to make turns
quickly and easily. It is essential that this skill be
learned first at low speed.
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 footrest to the outside
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.
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7
CROSSING A SLOPE
WARNING
EWB01632Improperly crossing hills or turning on hills
could cause loss of control or cause the ATV to
overturn.
Always follow proper procedures as de-
scribed in the Owner
’s Manual.
Avoid hills with excessively slippery or loose
surfaces.
Avoid crossing the side of a steep hill.
Shift your weight to the uphill side of the
ATV.
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.Traversing a sloping surface on your ATV requires
you to properly position your weight to maintain
proper balance. Be sure that you have learned the
basic riding skills on flat ground before attempting
to cross a sloping surface. Avoid slopes with slip-
pery surfaces or rough terrain that may upset your
balance. As you travel across a slope, lean your body in the
uphill direction. It may be necessary to correct the
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.U1PD60E0.book Page 18 Monday, June 13, 2011 2:57 PM

8-8
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EBU23071TIP
Some maintenance items need more frequent service if you are riding in unusually wet, dusty, sandy or
muddy areas, or at full-throttle.
Hydraulic brake service
Regularly check and, if necessary, correct the brake fluid level.
 Every two years replace the internal components of the brake master cylinders and calipers, and
change the brake fluid.
 Replace the brake hoses every four years and if cracked or damaged.23 *Moving parts and
cables 
Lubricate. √√√√
24 *Throttle lever 
Check operation.
 Check throttle lever free play, and adjust if neces-
sary.
 Lubricate cable and lever housing. √√√√√
25 *Front and rear brake
switches 
Check operation and correct if necessary. √√√√√
26 *Lights and switches 
Check operation and correct if necessary.
 Adjust headlight beams. √√√√√
NO. ITEM
CHECK OR MAINTENANCE
JOB INITIAL EVERY
Whichev- er comes first month136612
km
(mi) 320
(200) 1300
(800) 2500
(1600) 2500
(1600) 5000
(3200)
hours 20 80 160 160 320U1PD60E0.book Page 8 Monday, June 13, 2011 2:57 PM

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To remove the spark plug
1. Remove the seat. (See page 4-12.)
2. Remove the bolts and the quick fastener screws shown.
3. Remove the fuel tank cap by turning it coun- terclockwise. WARNING! Never remove the
fuel tank cap while smoking, or in the vi-
cinity of sparks, open flames, or other
sources of ignition such as pilot lights of
water heaters and clothes dryers. 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, as it is still very hot. Do not spill
gasoline on the engine, exhaust pipe or
muffler.
[EWB01871]
4. Pull the panel backward, and then remove the panel.
5. Install the fuel tank cap by turning it clockwise.
6. Remove the bolt, and then lift the rear of the fuel tank while sliding the tank slightly rear-
ward.1. Panel
2. Bolt
3. Quick fastener screw
4. Fuel tank cap
2
4 3 1
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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).
TIPIf 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.
3. 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/CR8E1. Spark plug gapSpark plug gap:0.7 –0.8 mm (0.028– 0.031 in)
U1PD60E0.book Page 13 Monday, June 13, 2011 2:57 PM

8-28
817. Install the seat.
TIPThe 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.EBU27703Cleaning the spark arrester Select a well-ventilated area free of combustible
materials and make sure the exhaust and muffler
are cool. 1. Remove the tailpipe 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.
1. Tailpipe bolt
1
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TIPIf the cable length cannot be adjusted to specifica-
tion, consult a Yamaha dealer.6. Tighten the locknut on the brake cable.
7. Slide the rubber cover to its original position.
8. Turn in the adjusting bolt at the rear brake cal-iper until it feels tight, then turn it out 1/8 turn
and tighten its locknut to the specified torque.
NOTICE: When tightening the locknut, hold the adjusting bolt with a wrench so
that it does not turn together with the lock-
nut.
[ECB00521]
WARNING
EWB02090Operating with improperly serviced or adjust-
ed brakes could cause the brakes to malfunc-
tion, resulting in reduced braking
performance. This could increase the chance
of a collision or accident. After adjusting the
parking brake free play, block the rear of the
ATV off the ground and spin the rear wheels.
Check to make sure there is no brake drag. If
brake drag is noticed, perform the adjustment
again.EBU24743Brake light switches The brake light, which is activated by the brake
pedal and brake lever, should come on just before
braking takes effect.
1. Locknut
2. Parking brake free play adjusting nut
3. Rubber cover
(a)
(b)
1
2
3
Tightening torque: Locknut (rear brake caliper):16 Nm (1.6 m ·kgf, 12 ft· lbf)
U1PD60E0.book Page 38 Monday, June 13, 2011 2:57 PM