2012 YAMAHA YFZ450 light

8-11
8
To remove the spark plug
1. Remove the seat. (See page 4-12.)
2. Remove the bolts and the quick fastener screws shown.
3. Remove the fuel tank cap by turning it coun- terclockwise. WARNING! Never remove the
fuel tank cap while smoking, or in the vi-
cinity of sparks, open flames, or other
sources of ignition such as pilot lights of
water heaters and clothes dryers. Always
turn off the engine before removing the
fuel tank cap. Do not remove the fuel tank
cap immediately after the engine has been
running, as it is still very hot. Do not spill
gasoline on the engine, exhaust pipe or
muffler.
[EWB01871]
4. Pull the panel backward, and then remove the panel.
5. Install the fuel tank cap by turning it clockwise.
6. Remove the bolt, and then lift the rear of the fuel tank while sliding the tank slightly rear-
ward.1. Panel
2. Bolt
3. Quick fastener screw
4. Fuel tank cap
2
4 3 1
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8
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).
TIPIf 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.
3. 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/CR8E1. Spark plug gapSpark plug gap:0.7 –0.8 mm (0.028– 0.031 in)
U1PD60E0.book Page 13 Monday, June 13, 2011 2:57 PM

8-28
817. Install the seat.
TIPThe air filter element should be cleaned every 20
–
40 hours. It should be cleaned and lubricated more
often if the ATV is operated in extremely dusty ar-
eas. Each time the air filter element maintenance
is performed, check the air inlet of the air filter case
for obstructions. Check the air filter case rubber
joint to the carburetor fittings and the rubber joint
manifold fittings for an air-tight seal. Tighten all fit-
tings securely to avoid the possibility of unfiltered
air entering the engine.EBU27703Cleaning the spark arrester Select a well-ventilated area free of combustible
materials and make sure the exhaust and muffler
are cool. 1. Remove the tailpipe 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.
1. Tailpipe bolt
1
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8
TIPIf the cable length cannot be adjusted to specifica-
tion, consult a Yamaha dealer.6. Tighten the locknut on the brake cable.
7. Slide the rubber cover to its original position.
8. 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: When tightening the locknut, hold the adjusting bolt with a wrench so
that it does not turn together with the lock-
nut.
[ECB00521]
WARNING
EWB02090Operating 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.EBU24743Brake light switches The brake light, which is activated by the brake
pedal and brake lever, should come on just before
braking takes effect.
1. Locknut
2. Parking brake free play adjusting nut
3. Rubber cover
(a)
(b)
1
2
3
Tightening torque: Locknut (rear brake caliper):16 Nm (1.6 m ·kgf, 12 ft· lbf)
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8
The brake light switch for the brake pedal can be
adjusted as follows, but the front brake light switch
should be adjusted by a Yamaha dealer.
Turn the rear brake light switch 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 adjusting nut in direction (b).
EBU30600Adjusting 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. Slide the rubber cover back at the clutch lever.
2. Loosen the locknut.
3. 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).1. Rear brake light switch
2. Rear brake light switch adjusting nut
(a) (b)1
2
1. Clutch lever free play
2. Locknut
3. Clutch lever free play adjusting bolt
4. Rubber cover1 3
4
(a)
(b)
2
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8
2. Remove the blown fuse, and then install a
new fuse of the specified amperage.
WARNING! Always use a fuse of the spec- ified rating, and never use a substitute ob-
ject in place of the proper fuse. An
improper fuse or a substitute object can
cause damage to the electrical system,
which could lead to a fire.
[EWB02172]
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.EBU30680Replacing 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 unit
2. Bolt
2 1
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84. Remove the headlight bulb holder by pushing
it in and turning it counterclockwise, and then
remove the burnt-out bulb. 5. Place a new headlight bulb into position.
NOTICE: Do not touch the glass part of the
headlight bulb to keep it free from oil, oth-
erwise the transparency of the glass, the
luminosity of the bulb, and the bulb life will
be adversely affected. Thoroughly clean
off any dirt and fingerprints on the head-
light bulb using a cloth moistened with al-
cohol or thinner.
[ECB00651]
1. Headlight bulb holder cover
2. Headlight coupler
1
2
1. Headlight bulb holder
1
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8
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.
EBU25551Adjusting a headlight beam NOTICEECB00690It 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).EBU25613Replacing the tail/brake light bulb If the tail/brake light bulb burns out, replace it as
follows. 1. Remove the tail/brake light bulb holder (to- gether with the bulb) by turning it counter-
clockwise.
1. Do not touch the glass part of the bulb.
1
1. Headlight beam adjusting screw
1 (a)
(b)
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