2006 YAMAHA YFZ450 ignition

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8Always turn off the engine when refueling.
8Do not refuel immediately after the engine
has been running and is still very hot.
8Do not spill gasoline on the engine or
exhaust pipe/muffler when refueling.
Never refuel while smoking or in the vicini-
ty of sparks, open flames, or other
sources of ignition such as the pilot lights
of water heaters and clothes dryers.
Gasoline can catch fire. You could be
burned.
8When transporting the machine in another
vehicle, be sure it is kept upright and that
the fuel cock is in the “OFF” position.
Otherwise, fuel may leak out of the carbu-
retor or fuel tank.
8Gasoline is poisonous. If you should swal-
low some gasoline or inhale a lot of gaso-
line vapor, or get some gasoline in your
eyes, see your doctor immediately. If
gasoline spills on your skin, wash with
soap and water. If gasoline spills on your
clothing, change your clothes.
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EBU11580
Engine stop switch “ENG. STOP”
Make sure that the engine stop switch is in the
“RUN” position before starting the engine. The
engine stop switch controls ignition and can be
used at all times to stop the engine, especially in
an emergency. The engine will not start or run
when the engine stop switch is turned to “OFF”.1
2
3
1. Light switch “LIGHTS”
2. Engine stop switch “ENG. STOP”
3. Start switch “START”
1. Contacteur d’éclairage “LIGHTS”
2. Coupe-circuit du moteur “ENG. STOP”
3. Contacteur du démarreur “START”
1. Interruptor de luces “LIGHTS”
2. Interruptor de paro del motor “ENG. STOP”
3. Interruptor de arranque “START”
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4-15
1. Clutch lever1. Levier d’embrayage1. Palanca de embrague
EBU00690
Clutch lever
The clutch lever is located on the left handlebar
and the ignition circuit cut-off system is incorpo-
rated in the clutch lever holder. Pull the clutch
lever to the handlebar to disengage the clutch,
and release the lever to engage the clutch. The
lever should be pulled rapidly and released
slowly for smooth clutch operation. (Refer to
“Starting a cold engine” for a description of the
ignition circuit cut-off system.)
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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)
5TG-9-62 5-6 5/13/05 1:45 PM Page 6-5

8-55
EBU14142
Spark plug inspection
Removal
1. Remove the seat. (See page 4-27 for seat
removal and installation procedures.)
2. Remove the bolts and the quick fastener
screws.
3. Remove the fuel tank cap by turning it
counterclockwise.
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8Always turn off the engine when removing
the fuel tank cap.
8Do not remove the fuel tank cap immedi-
ately after the engine has been running
and is still very hot.
8Do not spill gasoline on the engine,
exhaust pipe or muffler.
8Never remove the fuel tank cap while
smoking, or in the vicinity of sparks, open
flames, or other sources of ignition such
as the pilot lights of water heaters and
clothes dryers.
1. Panel 2. Bolt (×2)
3. Quick fastener screw (×2) 4. Fuel tank cap
1. Cache 2. Boulon (×2)
3. Vis à serrage rapide (×2)
4. Bouchon du réservoir de carburant
1. Panel 2. Perno (×2)
3. Perno del fijador rápido (×2)
4. Tapón del depósito de combustible
5TG-9-62 8 5/13/05 1:48 PM Page 8-55

8-63
NOTE:
If a torque wrench is not available when you are
installing a spark plug, a good estimate of the
correct torque is 1/4 to 1/2 turn past finger tight.
Have the spark plug tightened to the specified
torque as soon as possible.
4. Install the spark plug cap.
cC
Do not use any tools to remove or install the
spark plug cap, otherwise the ignition coil
coupler may be damaged. The spark plug
cap may be difficult to remove because the
rubber seal on the end of the cap fits tightly.
To remove the spark plug cap, simply twist it
back and forth while pulling it out; to install
it, twist it back and forth while pushing it in.
5. Place the fuel tank in the original position,
and then install the bolt.
6. Remove the fuel tank cap by turning it
counterclockwise.
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Battery electrolyte is poisonous and danger-
ous, causing severe burns, etc. It contains
sulfuric acid. Avoid contact with skin, eyes
or clothing.
Antidote:
EXTERNAL: Flush with water.
INTERNAL: Drink large quantities of water or
milk. Follow with milk of magnesia, beaten
egg or vegetable oil. Call a physician imme-
diately.
EYES: Flush with water for 15 minutes and
get prompt medical attention.
Batteries produce explosive gases. Keep
sparks, flame, cigarettes or other sources of
ignition away. Ventilate when charging or
using in an enclosed space. Always shield
your eyes when working near batteries.
KEEP OUT OF REACH OF CHILDREN.
5TG-9-62 9-11 5/12/05 6:14 PM Page 8-131

8-145
EBU04130
Troubleshooting
Although Yamaha machines receive a rigid
inspection before shipment from the factory,
trouble may occur during operation.
Any problem in the fuel, compression, or ignition
systems can cause poor starting and loss of
power. The troubleshooting chart describes a
quick, easy procedure for making checks. If your
machine requires any repair, take it to a
Yamaha dealer.
The skilled technicians at a Yamaha dealership
have the tools, experience, and know-how to
properly service your machine. Use only gen-
uine Yamaha parts on your machine. Imitation
parts may look like Yamaha parts, but they are
often inferior. Consequently, they have a shorter
service life and can lead to expensive repair
bills.
5TG-9-62 9-11 5/12/05 6:14 PM Page 8-145