YAMAHA YFZ450 2007 Owners Manual

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settings without sufficient technical knowl-
edge may result in poor performance of or
damage to the engine.
EBU24030
Checking the engine idling speed
A special tester is needed to check the engine
idling speed on this model.
Therefore, take the ATV to a Yamaha dealer to
have the engine idling speed checked and adjust-
ed.
EBU24043
Adjusting the throttle cable free play
The throttle cable free play should be checked
and, if necessary, adjusted at the intervals speci-
fied in the periodic maintenance and lubrication
chart.
The throttle cable free play should measure 2.0–
4.0 mm (0.08–0.16 in) at the throttle lever. Period-
ically check the throttle cable free play and, if nec-
essary, adjust it as follows.
NOTE:

The engine idling speed must be checked, and ad-
justed if necessary, before adjusting the throttle ca-
ble free play.
1. Loosen the locknut.
2. To increase the throttle cable free play, turn
the adjusting bolt in direction (a). To decrease
the throttle cable free play, turn the adjusting
bolt in direction (b).
3. Tighten the locknut. Engine idling speed:
1750–1850 r/min
1. Locknut
2. Throttle cable free play adjusting bolt
3. Throttle lever free play
3 2
1
(a)(b)

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EBU24060
Valve clearance
The valve clearance changes with use, resulting in
improper air-fuel mixture and/or engine noise. To
prevent this from occurring, the valve clearance
must be adjusted by a Yamaha dealer at the inter-
vals specified in the periodic maintenance and lu-
brication chart.
EBU24130
Checking the front and rear brake pads
The front and rear brake pads must be checked for
wear at the intervals specified in the periodic main-
tenance and lubrication chart.
EBU27711
Front brake pads
Each brake pad is provided with wear indicator
grooves, which allow you to check the brake pad
wear without having to disassemble the brake. To
check the brake pad wear, check the wear indica-
tor grooves. If a brake pad has worn to the point
that the wear indicator grooves are almost in con-
tact with the disc plate, have a Yamaha dealer re-
place the brake pads as a set.
NOTE:

The wheels need to be removed to check the
brake pads. (See page 8-50.)
EBU27721
Rear brake pads
Each brake pad is provided with wear indicator
grooves, which allow you to check the brake pad
wear without having to disassemble the brake. To
check the brake pad wear, check the wear indica-
tor grooves. If a brake pad has worn to the point
that the wear indicator grooves are almost in con-
tact with the disc plate, have a Yamaha dealer re-
1. Wear indicator groove
1

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place the brake pads as a set.
EBU26831
Checking the brake fluid level
Insufficient brake fluid may allow air to enter the
brake system, possibly causing it to become inef-
fective.
Before riding, check that the brake fluid is above
the minimum level mark and replenish if neces-
sary. A low brake fluid level may indicate worn
brake pads and/or brake system leakage. If the
brake fluid level is low, be sure to check the brake
pads for wear and the brake system for leakage.
Front brake
1. Wear indicator groove
1

1. Minimum level mark1

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Rear brakeNOTE:

To check the rear brake fluid level, remove the
seat. (See page 4-11.)
If the rear brake fluid level is low, replenish as fol-
lows.
1. Remove the brake fluid reservoir bracket bolt.2. Pull the brake fluid reservoir out to the side as
shown.
1. Minimum level mark
1

1. Bolt
1

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CAUTION:

ECB00780
Do not tilt the rear brake fluid reservoir exces-
sively when removing or installing the rear
brake fluid reservoir. Also do not twist or pull
the hose of the reservoir.
3. Remove the brake fluid reservoir cap, and
then refill with brake fluid.
4. Install the brake fluid reservoir cap.
5. Insert the projection on the brake fluid reser-
voir bracket into the hole in the frame.6. Install the brake fluid reservoir bracket bolt.
Observe these precautions:

When checking the fluid level, make sure that
the top of the brake fluid reservoir is level.

Use only the recommended quality brake fluid,
otherwise the rubber seals may deteriorate,
causing leakage and poor braking performance.
1. Brake fluid reservoir cap
1

1. Frame
2. Projection
3. Brake fluid reservoir bracket
4. Bolt
Recommended brake fluid:
DOT 4
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Refill with the same type of brake fluid. Mixing
fluids may result in a harmful chemical reaction
and lead to poor braking performance.

Be careful that water does not enter the brake
fluid reservoir when refilling. Water will signifi-
cantly lower the boiling point of the fluid and may
result in vapor lock.

Brake fluid may deteriorate painted surfaces or
plastic parts. Always clean up spilled fluid imme-
diately.

As the brake pads wear, it is normal for the brake
fluid level to gradually go down. However, if the
brake fluid level goes down suddenly, have a
Yamaha dealer check the cause.
EBU24290
Changing the brake fluid
Have a Yamaha dealer change the brake fluid at
the intervals specified in the NOTE after the peri-
odic maintenance and lubrication chart. In addi-
tion, have the oil seals of the master cylinders and
calipers as well as the brake hoses replaced at the
intervals listed below or whenever they are dam-
aged or leaking.

Oil seals: Replace every two years.

Brake hoses: Replace every four years.
EBU24390
Checking the front brake lever free play
The brake lever free play must be checked at the
intervals specified in the periodic maintenance and
lubrication chart. The brake lever should have a
free play of zero mm (zero in) as shown. If the free
play is incorrect, have a Yamaha dealer check the
brake system.
WARNING

EWB02070
Operating with improperly serviced or adjust-
ed brakes could cause loss of braking ability,
which could lead to an accident.
1. Brake lever free play
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After servicing:

Make sure the brakes operate smoothly and
that the free play is correct.

Make sure the brakes do not drag.

Make sure the brakes are not spongy. All air
must be bled from the brake system.
Replacement of brake components requires
professional knowledge. These procedures
should be performed by a Yamaha dealer.
EBU24611
Checking the brake pedal position
The brake pedal position must be checked and, if
necessary, adjusted at the intervals specified in
the periodic maintenance and lubrication chart.
The top of the brake pedal should be positioned
11.7 mm (0.46 in) below the top of the footrest as
shown. If the brake pedal is not positioned as spec-
ified, have a Yamaha dealer adjust it.WARNING

EWB02110
Operating with improperly serviced or adjust-
ed brakes could cause loss of braking ability,
which could lead to an accident.
After servicing:

Make sure the brakes operate smoothly and
that the brake pedal position is correct.

Make sure the brakes do not drag.

Make sure the brakes are not spongy. All air
must be bled from the brake system.
Replacement of brake components requires
professional knowledge. These procedures
1. Brake pedal position
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should be performed by a Yamaha dealer.
EBU24710
Adjusting the parking brake free play
The parking brake free play must be checked and,
if necessary, adjusted at the intervals specified in
the periodic maintenance and lubrication chart.
Cable length “A” should measure 47–51 mm (1.9–
2.0 in). Adjust the parking brake free play as fol-
lows.
1. Release the parking brake by moving theparking brake lever to the right.
2. Fully loosen the locknut and the adjusting bolt
at the rear brake caliper.
3. Loosen the locknut on the brake cable.
4. Turn the adjusting nut on the brake cable in di-
rection (a) to increase the cable length, and in
direction (b) to decrease it.
NOTE:

If the cable length cannot be adjusted to specifica-
tion, consult a Yamaha dealer.
5. Tighten the locknut on the brake cable.
1. Adjusting bolt
2. Cable length “A”
3. Locknut
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1. Locknut
2. Adjusting nut
(a)
(b)
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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)
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