2012 YAMAHA YFZ450 check engine

EBU17420
TABLE OF CONTENTS
LOCATION OF THE WARNING AND
SPECIFICATION LABELS ............................ 1-1
SAFETY INFORMATION .............................. 2-1
DESCRIPTION .............................................. 3-1Left 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 .................. 4-2
Handlebar switches .................................... 4-3
Throttle lever .............................................. 4-3
Speed limiter .............................................. 4-4
Clutch lever ................................................ 4-5
Brake lever ................................................. 4-5
Brake pedal ................................................ 4-6
Parking brake lever .................................... 4-6
Shift pedal .................................................. 4-7
Fuel tank cap .............................................. 4-8
Fuel ............................................................ 4-8 Fuel cock ..................................................4-10
Starter (choke) ..........................................4-11
Seat ..........................................................4-12
Adjusting the front shock absorber
assemblies ..............................................4-13
Adjusting the rear shock absorber assembly .................................................4-14
PRE-OPERATION CHECKS ..........................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
Chassis fasteners .......................................5-7
Instruments, lights and switches .................5-7
OPERATION...................................................6-1 Starting a cold engine .................................6-1
Starting a warm engine ...............................6-3
Shifting ........................................................6-3
Engine break-in ...........................................6-5U1PD60E0.book Page 1 Monday, June 13, 2011 2:57 PM

Parking ....................................................... 6-5
Parking on a slope ..................................... 6-6
Accessories and loading ............................ 6-7
RIDING YOUR ATV ...................................... 7-1 GETTING TO KNOW YOUR ATV............... 7-2
RIDE WITH CARE AND GOOD JUDGMENT .............................................. 7-2
BE CAREFUL WHERE YOU RIDE ............. 7-9
TURNING YOUR ATV .............................. 7-12
CLIMBING UPHILL ................................... 7-13
RIDING DOWNHILL.................................. 7-16
CROSSING A SLOPE............................... 7-18
CROSSING THROUGH SHALLOW WATER ................................................... 7-19
RIDING OVER ROUGH TERRAIN ........... 7-20
SLIDING AND SKIDDING ......................... 7-21
WHAT TO DO IF... .................................... 7-22
WHAT TO DO... ........................................ 7-22
PERIODIC MAINTENANCE AND
ADJUSTMENT ............................................... 8-1 Owner’s manual and tool kit ....................... 8-2
Periodic maintenance chart for the emission control system ........................... 8-3
General maintenance and lubrication chart ......................................................... 8-5 Removing and installing the panel ..............8-9
Checking the spark plug ...........................8-10
Engine oil and oil filter element .................8-14
Coolant .....................................................8-20
Cleaning the air filter element ...................8-24
Cleaning the spark arrester ......................8-28
Adjusting the carburetor ............................8-30
Checking the engine idling speed .............8-30
Adjusting the throttle lever free play .........8-31
Valve clearance ........................................8-31
Brakes .......................................................8-32
Checking the front and rear brake pads ...8-32
Checking the brake fluid level ...................8-33
Changing the brake fluid ...........................8-36
Checking the front brake lever free play ...8-36
Checking the brake pedal height ..............8-36
Adjusting the parking brake free play .......8-37
Brake light switches ..................................8-38
Adjusting the clutch lever free play ...........8-39
Drive chain slack .......................................8-41
Lubricating the drive chain ........................8-43
Checking and lubricating the cables .........8-43
Checking and lubricating the brake and
clutch levers ............................................8-44
Checking the shift pedal ...........................8-45
Checking and lubricating the brake pedal .......................................................8-45
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2-3
2speed 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
EWB00072Avoid Carbon Monoxide Poisoning
All engine exhaust contains carbon monoxide,
a deadly gas. Breathing carbon monoxide can
cause headaches, dizziness, drowsiness, nau-
sea, confusion, and eventually death.
Carbon Monoxide is a colorless, odorless,
tasteless gas which may be present even if you
do not see or smell any engine exhaust. Deadly
levels of carbon monoxide can collect rapidly
and you can quickly be overcome and unable
to save yourself. Also, deadly levels of carbon
monoxide can linger for hours or days in en-
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4-2
4
EBU17805Indicator light and warning light EBU17860Neutral indicator light“”
This indicator light comes on when the transmis-
sion is in the neutral position.EBU17930Coolant temperature warning light “”
This warning light comes on when the engine over-
heats. When this occurs during operation, stop the
engine as soon as it is safe to do so and allow it to
cool down for about 10 minutes. The electrical circuit of the warning light can be
checked according to the following procedure.
1. Set the engine stop switch to “” and turn
the key to “ON ”.
2. Shift the transmission into the neutral position or pull the clutch lever.
3. Push the start switch. If the warning light does not come on while the start switch is pushed,
have a Yamaha dealer check the electrical cir-
cuit.
NOTICEECB00010
The engine may overheat if the ATV is over-
loaded. In this case, reduce the load to spec-
ification.
Start the engine after making sure that the
warning light is out. Continuous use while
the warning light is on may cause damage to
the engine.
1. Neutral indicator light “N”
2. Coolant temperature warning light “”
12
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4-4
4
Regulate the speed of the ATV by varying the
throttle position. Because the throttle is spring-
loaded, the ATV will decelerate, and the engine will
return to an idle any time the throttle lever is re-
leased.
Before starting the engine, check the throttle to be
sure it is operating smoothly. Make sure it returns
to the idle position as soon as the lever is released.
EBU18323Speed limiter Your ATV is equipped with an adjustable speed
limiter. The speed limiter keeps the throttle from
fully opening, even when the throttle lever is
pushed to the maximum.
1. Loosen the locknut.
2. To increase the maximum engine power avail- able and the maximum speed of the ATV, turn
the adjusting screw in direction (a). To de-
crease the maximum engine power available
and the maximum speed of the ATV, turn the
adjusting screw in direction (b). Do not turn
the adjusting screw out more than 12 mm
(0.47 in) or the throttle cable could be dam-
aged. Always make sure the throttle lever free
play is adjusted to 2.0– 4.0 mm (0.08–0.16 in).
(See page 8-31.) WARNING! Improper ad-
justment of the speed limiter and throttle
could cause throttle cable damage or im-
proper throttle operation. You could lose
control, resulting in an accident.
[EWB00241]
1. Throttle leverU1PD60E0.book Page 4 Monday, June 13, 2011 2:57 PM

5-1
5
EBU19201
PRE-OPERATION CHECKS
EBU19224Inspect your vehicle each time you use it to make sure the vehicle is in safe operating condition. Always
follow the inspection and maintenance procedures and schedules described in the Owner’s Manual.
WARNING
EWB00481Failure to inspect or maintain the vehicle properly increases the possibility of an accident or equip-
ment damage. Do not operate the vehicle if you find any problem. If a problem cannot be corrected
by the procedures provided in this manual, have the vehicle inspected by a Yamaha dealer.Before using this vehicle, check the following points:
ITEM ROUTINE PAGE
Fuel 
Check fuel level in fuel tank, and add recommended fuel if neces-
sary.
 Check fuel line for leakage. Correct if necessary. 4-8, 5-4
Engine oil 
Check oil level in engine oil tank, and add recommended oil to spec-
ified level if necessary.
 Check ATV for oil leakage. Correct if necessary. 5-4, 8-14
Coolant 
Check coolant level in reservoir, and add recommended coolant to
specified level if necessary.
 Check cooling system for leakage. Correct if necessary. 5-4, 8-20
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5-4
5
EBU19541Fuel Make sure that there is sufficient fuel in the tank.
(See page 4-8.)EBU19560Engine oil Make sure that the engine oil is at the specified lev-
el. Add oil as necessary. (See page 8-14.)EBU19631Coolant Make sure that the coolant is at the specified level.
Add coolant as necessary. (See page 8-20.)TIPThe coolant level must be checked on a cold en-
gine since the level varies with engine tempera-
ture.EBU19712Front and rear brakes Brake lever and brake pedal
Check that there is no free play in the brake le-
ver. If there is free play, have a Yamaha dealer
check the brake system.

Check for correct brake pedal height. (See page
8-36.) If the pedal height is incorrect, have a
Yamaha dealer adjust it.
Check the operation of the lever and pedal. They
should move smoothly and there should be a
firm feeling when the brakes are applied. If not,
have a Yamaha dealer check the brake system.
Brake fluid level
Check the brake fluid level. Add fluid if necessary.
(See page 8-33.)
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 8-32.) Specified brake fluid:
DOT 4
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6-1
6
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).
U1PD60E0.book Page 1 Monday, June 13, 2011 2:57 PM