2009 YAMAHA YFZ450R light

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EBU29440
Checking the spark plug
The spark plug is an important engine component,
which should be checked periodically, preferably
by a Yamaha dealer. Since heat and deposits will
cause any spark plug to slowly erode, the spark
plug should be removed and checked in accor-
dance with the periodic maintenance and lubrica-
tion chart. In addition, the condition of the spark
plug can reveal the condition of the engine.
The porcelain insulator around the center elec-
trode of the spark plug should be a medium-to-light
tan (the ideal color when the vehicle is ridden nor-
mally). If the spark plug shows a distinctly different
color, the engine could be operating improperly.
Do not attempt to diagnose such problems your-
self. Instead, have a Yamaha dealer check the ve-
hicle.
If a spark plug shows signs of electrode erosion
and excessive carbon or other deposits, it should
be replaced.
Before installing a spark plug, the spark plug gap
should be measured with a wire thickness gaugeand, if necessary, adjusted to specification.
Clean the surface of the spark plug gasket and its
mating surface, and then wipe off any grime from
the spark plug threads.
Specified spark plug:
NGK/CR8E
1. Spark plug gap
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
Tightening torque:
Spark plug:
12.5 Nm (1.3 m·kgf, 9.4 ft·lbf)

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EBU27701
Cleaning the spark arrester
Select a well-ventilated area free of combustible
materials and make sure the exhaust and muffler
are cool.
1. Remove the bolt.
2. Remove the tailpipe by pulling it out of the
muffler.
3. Tap the tailpipe lightly, and then use a wire
brush to remove any carbon deposits from the
spark arrester portion of the tailpipe and inside
of the tailpipe housing.4. Insert the tailpipe into the muffler and align the
bolt holes.
5. Install the bolt and tighten it to the specified
torque.
6. Remove the purging bolt.
1. Bolt
1

1. Tailpipe
2. Spark arrester
Tightening torque:
Tailpipe bolt:
8 Nm (0.8 m·kgf, 5.8 ft·lbf)
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6. Turn in the adjusting bolt at the rear brake cal-
iper until it feels tight, then turn it out 1/8 turn
and tighten its locknut to the specified torque.
NOTICE

ECB00520
When tightening the locknut, hold the adjust-
ing bolt with a wrench so that it does not turn
together with the locknut.
WARNING

EWB02090
Operating with improperly serviced or adjust-
ed brakes could cause the brakes to malfunc-
tion, resulting in reduced braking
performance. This could increase the chance
of a collision or accident. After adjusting the
parking brake free play, block the rear of the
ATV off the ground and spin the rear wheels.
Check to make sure there is no brake drag. If
brake drag is noticed, perform the adjustment
again.
EBU24740
Brake light switches
The operation of the brake light switches must be
checked and, if necessary, adjusted at the inter-
vals specified in the periodic maintenance and lu-
brication chart.
The brake light switch for the brake pedal can be
adjusted as follows, but the other brake light
switches should be adjusted by a Yamaha dealer.
TIP

The brake light switch is properly adjusted when
the brake light comes on just before braking takes
effect.
Turn the adjusting nut while holding the brake light
switch in place. To make the brake light come on
earlier, turn the adjusting nut in direction (a). To
make the brake light come on later, turn the adjust-
ing nut in direction (b). Tightening torque:
Locknut (rear brake caliper):
16 Nm (1.6 m·kgf, 11 ft·lbf)

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EBU29541
Adjusting the clutch lever free play
The clutch lever free play must be checked and, if
necessary, adjusted at the intervals specified in
the periodic maintenance and lubrication chart.
The clutch lever free play should measure 8.0–
13.0 mm (0.31–0.51 in) as shown. If the free play
is incorrect, adjust it as follows.1. To increase the clutch lever free play, turn the
adjusting nut at the clutch lever in direction (a),
and to decrease it, turn the nut in direction (b).
If the specified free play cannot be obtained,
proceed with the following steps.
2. Fully turn the adjusting nut at the clutch lever
in direction (a) to loosen the clutch cable.
3. Loosen the locknut at the crankcase.
4. To increase the clutch lever free play, turn the
adjusting nut at the crankcase in direction (a),
and to decrease it, turn the nut in direction (b).
1. Brake light switch
2. Brake light switch adjusting nut
1
2(a)(b)

1. Clutch lever free play
2. Clutch lever free play adjusting nut
1
(a)
(b)
2

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EBU25242
Replacing the fuse
The fuse holder is located under the seat. (See
page 4-10.)
If the fuse is blown, replace it as follows.
1. Turn the key to “OFF” and turn off all electrical
circuits.
NOTICE

ECB00640
To prevent accidental short-circuiting, turn off
the main switch when checking or replacing a
fuse.
2. Remove the blown fuse, and then install a
new fuse of the specified amperage.
WARNING

EWB02171
Always use a fuse of the specified rating, and
never use a substitute object in place of the
proper fuse. An improper fuse or a substitute
object can cause damage to the electrical sys-
tem, which could lead to a fire.
3. Turn the key to “ON” and turn on the electrical
circuits to check if the devices operate.
4. If the fuse immediately blows again, have a
Yamaha dealer check the electrical system.
EBU29460
Replacing a headlight bulb
If a headlight bulb burns out, replace it as follows.
1. Remove panel E. (See page 8-8.)
2. Remove the headlight bulb holder cover.
1. Fuse
2. Spare fuse
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Specified fuse:
20.0 A

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3. Remove the headlight bulb holder by pushing
it in and turning it counterclockwise, and then
remove the burnt-out bulb.
WARNING

EWB02230
Do not touch a headlight bulb when it is on or
immediately after it is turned off. You can be
burned or a fire could start if the bulb touches
something flammable. Wait for the bulb to cool
before touching or removing it.
4. Place a new headlight bulb into position.
1. Headlight bulb holder cover
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1. Headlight bulb holder
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NOTICE

ECB00650
Do not touch the glass part of the headlight
bulb to keep it free from oil, otherwise the
transparency of the glass, the luminosity of the
bulb, and the bulb life will be adversely affect-
ed. Thoroughly clean off any dirt and finger-
prints on the headlight bulb using a cloth
moistened with alcohol or thinner.
5. Install the headlight bulb holder by pushing it
in and turning it clockwise.
6. Install the headlight bulb holder cover.7. Install the panel.
8. Adjust the headlight beam if necessary.
EBU25551
Adjusting a headlight beam
NOTICE
ECB00690
It is advisable to have a Yamaha dealer make
this adjustment.
To raise a headlight beam, turn the headlight beam
adjusting screw in direction (a).
To lower a headlight beam, turn the adjusting
screw in direction (b).
1. Do not touch the glass part of the bulb.
1. Headlight beam adjusting screw1
(a)
(b)

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EBU26920
Tail/brake light
This model is equipped with an LED type of tail/
brake light.
If the tail/brake light does not come on, have a
Yamaha dealer check it.
EBU25651
Removing a wheel
1. Place the ATV on a level surface.
2. Loosen the wheel nuts.
FrontRear
3. Elevate the ATV and place a suitable stand
under the frame.
4. Remove the nuts from the wheel.
5. Remove the wheel.
EBU25681
Installing a wheel
1. Place the ATV on a level surface.
2. Install the wheel and the nuts.
TIP


When installing a front wheel, make sure its ar-
row mark points toward the rotating direction
1. Wheel nut
1. Wheel nut