2008 YAMAHA YFZ450 tires

EBU17420
TABLE OF CONTENTS
SAFETY INFORMATION .............................. 1-1
LOCATION OF THE WARNING AND
SPECIFICATION LABELS ............................ 2-1
DESCRIPTION .............................................. 3-1
Left view ..................................................... 3-1
Right view................................................... 3-1
Controls and instruments ........................... 3-2
INSTRUMENT AND CONTROL
FUNCTIONS .................................................. 4-1
Main switch ............................................... 4-1
Indicator light and warning light ................. 4-1
Handlebar switches ................................... 4-2
Throttle lever ............................................. 4-3
Speed limiter ............................................. 4-4
Clutch lever ............................................... 4-5
Brake lever ................................................ 4-5
Brake pedal ............................................... 4-5
Parking brake lever ................................... 4-6
Shift pedal ................................................. 4-7
Fuel tank cap ............................................. 4-7
Fuel ........................................................... 4-8
Fuel cock ................................................... 4-9Starter (choke) “ ” .................................. 4-10
Seat ......................................................... 4-11
Adjusting the front shock absorber
assemblies ............................................. 4-12
Adjusting the rear shock absorber
assembly ................................................ 4-17
PRE-OPERATION CHECKS ..........................5-1
Pre-operation check list ............................. 5-1
Fuel ............................................................ 5-4
Engine oil ................................................... 5-4
Coolant ...................................................... 5-4
Front and rear brakes ................................ 5-4
Throttle lever .............................................. 5-5
Drive chain ................................................. 5-5
Tires ........................................................... 5-5
Measuring the tire pressure ....................... 5-6
Tire wear limit ............................................ 5-7
Chassis fasteners ...................................... 5-8
Instruments, lights and switches ................ 5-8
OPERATION...................................................6-1
Starting a cold engine ................................ 6-1
Starting a warm engine .............................. 6-3
Shifting ....................................................... 6-3
Engine break-in .......................................... 6-5

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ing, use the proper gear and maintain a steady
speed when climbing a hill. If you stall or roll
backwards, follow the special procedure for
braking described in this manual. Dismount on
the uphill side or to a side if pointed straight up-
hill. Turn the ATV around and remount, following
the procedure described in this manual.

Always check for obstacles before operating in a
new area.

Never attempt to operate over large obstacles,
such as large rocks or fallen trees. Always follow
proper procedures when operating over obsta-
cles as described in this manual.

Always be careful when skidding or sliding.
Learn to safely control skidding or sliding by
practicing at low speeds and on level, smooth
terrain. On extremely slippery surfaces, such as
ice, go slowly and be very cautious in order to re-
duce the chance of skidding or sliding out of con-
trol.

Never operate an ATV in fast flowing water or in
water deeper than that recommended in this
manual. Remember that wet brakes may have
reduced stopping ability. Test your brakes after
leaving water. If necessary, apply them several
times to let friction dry out the linings.

Always use the size and type of tires specified in
this manual.

Always maintain proper tire pressure as de-
scribed in this manual.

Never modify an ATV through improper installa-
tion or use of accessories.

Never exceed the stated load capacity for an
ATV. Cargo should be properly distributed and
securely attached. Reduce speed and follow in-
structions in this manual for carrying cargo or
pulling a trailer. Allow greater distance for brak-
ing.
WARNING

EWB00061

Always turn off the engine when refueling.

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

Do not spill gasoline on the engine or ex-
haust pipe/muffler when refueling. Never re-
fuel while smoking, or in the vicinity of
sparks, open flames, or other sources of ig-
nition such as the pilot lights of water heat-
ers and clothes dryers. Gasoline can catch
fire and you could be burned.

When transporting the ATV in another vehi-
cle, be sure it is kept upright and that the fuel

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6
5TG-21696-40
27.5 kPa0.275 kgf/cm
2
4.0 psi
30 kPa
0.30 kgf/cm
2
4.4 psi
GBDEF
INLPS
Set with tires cold.
Pneus ˆ froid. Bei kalten Reifen.
Ajuste con los
neum‡ticos an fr’o.Impostare a pneumatici
freddi.
StŠll in med kalla dŠck. Wanneer de banden
koud zijn.
Regular com pneus
frios.
For Europe For Oceania
6
27.5kPa, {0.275kgf/cm
2}, 4.0psi
30kPa, {0.30kgf/cm2}, 4.4psi
24.5kPa, {0.245kgf/cm2}, 3.5psi
27kPa, {0.27kgf/cm2}, 3.9psi
30
7

5-2
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Rear brake

Check operation. If soft or spongy, have Yamaha dealer bleed
hydraulic system.

Check brake pads for wear, and replace if necessary.

Check brake fluid level in reservoir, and add recommended brake
fluid to specified level if necessary.

Check hydraulic system for leakage. Correct if necessary.5-4, 8-31, 8-32, 8-36
Clutch

Check operation, and correct if necessary.

Lubricate cable if necessary.

Check lever free play, and adjust if necessary.8-39
Throttle lever

Make sure that operation is smooth. Lubricate cable and lever hous-
ing if necessary.

Check cable free play, and adjust if necessary.5-5, 8-30
Control cables

Make sure that operation is smooth. Lubricate if necessary. 8-41
Drive chain

Check chain slack, and adjust if necessary.

Check chain condition. Lubricate if necessary.5-5, , 8-41
Wheels and tires

Check wheel condition, and replace if damaged.

Check tire condition and tread depth. Replace if necessary.

Check air pressure. Correct if necessary.5-5, 5-6, 5-7
Brake and shift pedals

Make sure that operation is smooth. Lubricate pedal pivoting points
if necessary.8-43
Brake and clutch levers

Make sure that operation is smooth. Lubricate lever pivoting points
if necessary.8-42
Chassis fasteners

Make sure that all nuts, bolts and screws are properly tightened. 5-8
Instruments, lights and
switches

Check operation, and correct if necessary. 5-8
ITEM ROUTINE PAGE

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have a Yamaha dealer check the brake system.
Brake fluid level
Check the brake fluid level. Add fluid if necessary.
(See page 8-32.)
Brake fluid leakage
Check to see if any brake fluid is leaking out of the
pipe joints or brake fluid reservoirs. Apply the
brakes firmly for one minute. If there is any leak-
age, have a Yamaha dealer check the brake sys-
tem.
Brake operation
Test the brakes at slow speed after starting out to
make sure they are working properly. If the brakes
do not provide proper braking performance, check
the brake pads for wear. (See page 8-31.)
WARNING

EWB00580
Always check the brakes at the start of every
ride. Do not ride the ATV if you find any prob-
lem with the brakes or you could lose braking
ability, which could lead to an accident. If aproblem cannot be corrected by the adjust-
ment procedures provided in this manual, have
a Yamaha dealer check for the cause.
EBU19761
Throttle lever
Check the operation of the throttle lever. It must
open smoothly and spring back to the idle position
when released. Have a Yamaha dealer correct if
necessary.
EBU19770
Drive chain
Check the condition of the drive chain and check
the drive chain slack. Lubricate and adjust the
drive chain as necessary.
EBU19791
Tires
WARNING

EWB00601
Use of improper tires on this ATV, or operation
of this ATV with improper or uneven tire pres-
sure, may cause loss of control, increasing
your risk of accident.
Pay attention to the following.

The tires listed below have been approved
Recommended brake fluid:
DOT 4

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by Yamaha Motor Co., Ltd. for this model.
Other tire combinations are not recommend-
ed.
Front:
Manufacturer/model:
DUNLOP/KT341 Radial
Size:
AT21 x 7-10
Type:
Tubeless
Rear:
Manufacturer/model:
DUNLOP/KT355A Radial
Size:
AT20 x 10-9
Type:
Tubeless

The tires should be set to the recommended
pressure:
Recommended tire pressure:
Front:
27.5 kPa (4.0 psi) (0.275 kgf/cm
2
)
Rear:
30.0 kPa (4.4 psi) (0.300 kgf/cm
2
)

Check and adjust tire pressures when the
tires are cold.

Tire pressures must be equal on both
sides.

Tire pressure below the minimum speci-
fied could cause the tire to dislodge from
the rim under severe riding conditions.
Minimum tire pressure:
Front:
24.5 kPa (3.5 psi) (0.245 kgf/cm
2
)
Rear:
27.0 kPa (3.9 psi) (0.270 kgf/cm
2
)

Use no more than the following pressures
when seating the tire beads.
Maximum tire seating pressure:
Front:
250 kPa (36 psi) (2.5 kgf/cm
2
)
Rear:
250 kPa (36 psi) (2.5 kgf/cm
2
)
Higher pressures and fast inflation may
cause a tire to burst. Inflate the tires very
slowly and carefully.
EBU19820
Measuring the tire pressure
Use the low-pressure tire gauge.
NOTE:

The low-pressure tire gauge is included as stan-

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dard equipment. Make two measurements of the
tire pressure and use the second reading. Dust or
dirt in the gauge could cause the first reading to be
incorrect.
Set the tire pressure when the tires are cold. Set
the tire pressures to the following specifications:
EBU19830
Tire wear limit
Replace the tire when the tire groove decreases to
3 mm (0.12 in).
1. Low-pressure tire gauge
Recommended pressure:
Front
27.5 kPa (4.0 psi) (0.275 kgf/cm
2
)
Rear
30.0 kPa (4.4 psi) (0.300 kgf/cm
2
)
Minimum:
Front
24.5 kPa (3.5 psi) (0.245 kgf/cm
2
)
Rear
27.0 kPa (3.9 psi) (0.270 kgf/cm
2
)
Maximum:
Front
30.5 kPa (4.4 psi) (0.305 kgf/cm
2
)
Rear
33.0 kPa (4.8 psi) (0.330 kgf/cm
2
)

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CAUTION:

ECB00200
Always 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.
3. Shift into first gear.
4. Open the throttle gradually and at the same
time, release the clutch lever slowly.
5. Once the ATV has attained adequate speed,
release the throttle, and at the same time,
quickly pull in the clutch lever.
6. Shift the transmission into second gear.
(Make sure not to shift the transmission into
neutral)
7. Open the throttle part way and gradually re-
lease the clutch lever.
8. Follow the same procedure when shifting to
the next higher gear.
WARNING

EWB00730
Opening the throttle abruptly or releasing the
clutch lever too quickly could make the ATV
wheelie, which would increase the chance of
an accident, including an overturn.
EBU20650
To decelerate
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.WARNING
EWB00710
Make sure the engine has sufficiently slowed
before shifting to a lower gear. Engaging a low-
er gear when the engine speed is too high
could make the wheels stop rotating and lose
traction. This could cause loss of control, an
accident and injury. It could also cause engine
or drive train damage.
CAUTION:

ECB00180

Even with the transmission in the neutral po-
sition, do not coast for long periods of time
with the engine off, and do not tow the ATV
for long distances. The transmission is prop-
erly lubricated only when the engine is run-
ning. Inadequate lubrication may damage