2007 YAMAHA YFZ450 light

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kit.
To check the spark plug
1. Check that the porcelain insulator around the
center electrode of the spark plug is a medi-
um-to-light tan (the ideal color when the ATV
is ridden normally).
NOTE:

If the spark plug shows a distinctly different color,
the engine could be operating improperly. Do not
attempt to diagnose such problems yourself. In-
stead, have a Yamaha dealer check the ATV.
2. Check the spark plug for electrode erosionand excessive carbon or other deposits, and
replace it if necessary.
To install the spark plug
1. Measure the spark plug gap with a wire thick-
ness gauge and, if necessary, adjust the gap
to specification.
1. Spark plug wrench
1

Specified spark plug:
NGK/CR8E
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
1. Spark plug gap

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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.
6. Remove the purging bolt.
1. Bolt
1

1. Tailpipe
2. Spark arrester
1
2

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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.
CAUTION:

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.
NOTE:

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, 12 ft·lbf)

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EBU24820
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. Loosen the locknut at the clutch lever.
2. To increase the clutch lever free play, turn the
adjusting bolt at the clutch lever in direction
(a), and to decrease it, turn the bolt in direction
(b).
3. Tighten the locknut at the clutch lever.
If the specified free play cannot be obtained,
proceed with the following steps.
4. Loosen the locknut at the clutch lever.
5. Fully turn the adjusting bolt at the clutch lever
in direction (a) to loosen the clutch cable.
6. Loosen the locknut at the crankcase.
1. Brake light switch
2. Brake light switch adjusting nut
(a)
(b)1
2

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

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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.
EBU25440
Replacing a headlight bulb
If a headlight bulb burns out, replace it as follows.
1. Remove the headlight unit by removing the
bolts.2. Disconnect the headlight coupler.
3. Remove the headlight bulb holder cover. Specified fuse:
15.0 A
1. Headlight assembly
2. Bolt21

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4. Remove the headlight bulb holder by pushing
it in and turning it counterclockwise, and then
remove the defective 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.
5. Place a new headlight bulb into position.
1. Headlight bulb holder cover
2. Headlight coupler
1
2

1. Headlight bulb holder
1

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CAUTION:

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.
6. Install the headlight bulb holder by pushing it
in and turning it clockwise.
7. Install the headlight bulb holder cover.8. Connect the headlight coupler.
9. Install the headlight unit by installing the bolts.
10. Adjust the headlight beam if necessary.
EBU25550
Adjusting a headlight beam
CAUTION:

ECB00690
It is advisable to have a Yamaha dealer make
this adjustment.
To raise a headlight beam, turn the 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

1. Headlight beam adjusting screw
1(a)
(b)

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EBU25580
Replacing the tail/brake light bulb
If the tail/brake light bulb burns out, have a
Yamaha dealer replace it.
EBU25650
Removing a wheel
1. Loosen the wheel nuts.
FrontRear
2. Elevate the ATV and place a suitable stand
under the frame.
3. Remove the nuts from the wheel.
4. Remove the wheel.
EBU25670
Installing a wheel
1. Install the wheel and the nuts.
NOTE:

When installing a front wheel, make sure its arrow
mark points toward the rotating direction of the
wheel.
1. Nut
1. Nut