2006 YAMAHA YFZ450 engine

6-3
EBU14120
Starting a cold engine
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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
accident or collision.
1. Apply 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.
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6-5
NOTE:
This model is equipped with an ignition circuit
cut-off system. The engine can be started under
the following conditions.
8When the transmission is in neutral.
At this time the neutral indicator light should
come on. If the light does not come on, ask a
Yamaha dealer to inspect it.
8When the clutch is disengaged with the trans-
mission in any position. However, it is recom-
mended to shift into neutral before starting the
engine.
5. Use the starter (choke) in reference to the
figure:
Position
1: Cold engine start-
ambient temperature below 5 ° C.
Position 2: Cold engine start-
ambient temperature at 0 ° C -
30 ° C and warming up position.
Position 3: Cold engine start-
ambient temperature above 25 ° C
and warm engine start position.
1. Fully open 2. Half open
3. Closed a. Starter (choke)
1. Pleine course 2. Mi-course
3. Fermé a. Starter (choke)
1. Abierto completamente 2. Semiabierto
3. Cerrado a. Starter (choke)
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6-7
6. Completely close the throttle lever and start
the engine by pushing the start switch.
NOTE:
If the engine fails to start, release the start
switch, then push it again. Pause a few seconds
before the next attempt. Each cranking should
be as short as possible to preserve battery ener-
gy. Do not crank the engine more than 10 sec-
onds on each attempt.
7. If the engine is started with the starter
(choke) in position 1, the starter (choke)
should be returned to position 2to 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.
8. Continue warming up the engine until it
idles smoothly and return the starter
(choke) to position 3before riding.
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See the “Engine break-in” section prior to
operating the engine for the first time.
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6-9
EBU01800
Starting a warm engine
To start a warm engine, refer to the “Starting a
cold engine” section. The starter (choke) should
not be used. The throttle should be opened
slightly.
EBU01820
Warming up
To get maximum engine life, always warm up
the engine before starting off. Never accelerate
hard with a cold engine! To see whether or not
the engine is warm, check if it responds to the
throttle normally with the starter (choke) turned
off.
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6-11
1. Shift pedal N. Neutral position1. Pédale de sélection N. Point mort1. Pedal del cambio N. Punto muerto
EBU01981
Shifting
This model 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 its original position, apply the clutch and
repeatedly depress the shift pedal until it stops.
When it stops, it will be in first gear. Raise the
pedal slightly to neutral.
cC
8Do not coast for long periods with the
engine off, and do not tow the machine a
long distance. Even in neutral position, the
transmission is only properly lubricated
when the engine is running. Inadequate
lubrication may cause damage.
8Always use the clutch when changing
gears. The engine, transmission and drive
train are not designed to withstand the
shock of forced shifting and can be dam-
aged by shifting without the clutch.
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6-13
EBU14260
To start out and accelerate:
1. Release the throttle lever, and then release
the parking brake.
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Always close the throttle while 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 machine has attained adequate
speed, release the throttle, and at the
same time, quickly pull in the clutch lever.
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6-17
EBU02080
To decelerate:
When slowing down or stopping, release the
throttle 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 control and increasing the
possibility of an accident.
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Make sure the engine has sufficiently slowed
before shifting to a lower gear. Engaging a
lower gear when the engine speed is too
high could make the wheels stop rotating.
This could cause loss of control, an accident
and injury. It could also cause engine or
drive train damage.
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6-19
EBU02092
Engine break-in
There is never a more important period in the
life of your machine than the period between
zero and 20 hours.
For this reason, we ask that you carefully read
the following material. Because the engine is
brand new, you must not put an excessive load
on it for the first several hours of running. During
the first 20 hours, the various parts in the engine
wear and polish themselves to the correct oper-
ating clearances.
During this period, prolonged full throttle opera-
tion or any condition which might result in exces-
sive engine heating must be avoided. However,
momentary (2-3 seconds maximum) full throttle
operation under load does not harm the engine.
Each full throttle acceleration sequence should
be followed with a substantial rest period for the
engine by cruising at lower r/min so the engine
can rid itself of the temporary build up of heat.
If any abnormality is noticed during this period,
consult a Yamaha dealer.
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