2008 YAMAHA YFZ450 fuel

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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cock is in the “OFF” position. Otherwise, fuel
may leak out of the carburetor or fuel tank.

Gasoline is poisonous. If you should swal-
low some gasoline or inhale a lot of gasoline
vapor, or get some gasoline in your eyes,
seek medical help immediately. If gasoline
spills on your skin, wash with soap and wa-
ter. If gasoline spills on your clothing,
change your clothes.
WARNING

EWB00070
Always operate your ATV in an area with ade-
quate ventilation. Never start or run the engine
in a closed area. Exhaust fumes are poisonousand may cause loss of consciousness and
death within a short time.

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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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5 6

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WARNING

EWB00220

Always set the parking brake before starting
the engine. The ATV could start moving un-
expectedly if the parking brake is not ap-
plied. This could cause loss of control or a
collision.

Always be sure you have released the park-
ing brake before you begin to ride. The brake
could overheat if you ride the ATV without re-
leasing the parking brake. You could lose
braking performance which could cause an
accident. You could also wear out the brakes
prematurely.
EBU18530
Shift pedal
This ATV is equipped with a constant-mesh 5-
speed transmission. The shift pedal is located on
the left side of the engine and is used in combina-
tion with the clutch when shifting.
EBU18720
Fuel tank cap
Remove the fuel tank cap by turning it counter-
clockwise.
1. Shift pedal
1

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EBU18810
Fuel
Make sure that there is sufficient fuel in the tank.
Fill the fuel tank to the bottom of the filler tube as
shown.NOTE:

If knocking or pinging occurs, use a different brand
1. Fuel tank cap
1

1. Fuel level
2. Filler tube
Recommended fuel:
PREMIUM UNLEADED GASOLINE ONLY
For Europe: PREMIUM UNLEADED GASO-
LINE ONLY with a research octane number
of 97 or higher
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)

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of gasoline or higher octane grade.
CAUTION:

ECB00070
Use only unleaded gasoline. The use of leaded
gasoline will cause severe damage to internal
engine parts, such as the valves and piston
rings, as well as to the exhaust system.
WARNING

EWB00310

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.
EBU18820
Fuel cock
The fuel cock supplies fuel from the tank to the car-
buretor while also filtering it.The fuel cock lever positions are explained as fol-
lows and shown in the illustrations.
OFF
With the fuel cock lever in this position, fuel will not
flow. Always turn the fuel cock lever to this position
when the engine is not running.
1. Arrow mark positioned over “OFF”

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ON
With the fuel cock lever in this position, fuel flows
to the carburetor. Turn the fuel cock lever to this
position when starting the engine and riding.
RES
This indicates reserve. With the fuel cock lever in
this position, the fuel reserve is made available.
Turn the fuel cock lever to this position if you run
out of fuel while riding. When this occurs, refuel as
soon as possible and be sure to turn the fuel cock
lever back to “ON”!

EBU18850
Starter (choke) “”
Starting a cold engine requires a richer air-fuel mix-
ture, which is supplied by the starter (choke).
Move the starter (choke) in direction (a) to turn on
1. Arrow mark positioned over “ON”
1. Arrow mark positioned over “RES”