tow YAMAHA YZ450F 2006 Owners Manual

1 - 10
GEN
INFO
CONTROL FUNCTIONS
EC150000
CONTROL FUNCTIONS
EC151000
“ENGINE STOP” BUTTON
The “ENGINE STOP” button 1 is located on
the left handlebar. Continue pushing the
“ENGINE STOP” button till the engine comes
to a stop.
EC152000
CLUTCH LEVER
The clutch lever 1 is located on the left han-
dlebar; it disengages or engages the clutch.
Pull the clutch lever to the handlebar to disen-
gage the clutch, and release the lever to
engage the clutch. The lever should be pulled
rapidly and released slowly for smooth starts.
EC153000
SHIFT PEDAL
The gear ratios of the constant-mesh 5 speed
transmission are ideally spaced. The gears
can be shifted by using the shift pedal 1 on
the left side of the engine.
EC154000
KICK STARTER
Rotate the kick starter 1 away from the
engine. Push the starter down lightly with your
foot until the gears engage, then kick smoothly
and forcefully to start the engine. This model
has a primary kick starter so the engine can be
started in any gear if the clutch is disengaged.
In normal practices, however, shift to neutral
before starting.
1
EC155001
THROTTLE GRIP
The throttle grip 1 is located on the right han-
dlebar; it accelerates or decelerates the
engine. For acceleration, turn the grip toward
you; for deceleration, turn it away from you.

1 - 11
GEN
INFO
CONTROL FUNCTIONS
EC156000
FRONT BRAKE LEVER
The front brake lever 1 is located on the right
handlebar. Pull it toward the handlebar to acti-
vate the front brake.
EC157000
REAR BRAKE PEDAL
The rear brake pedal 1 is located on the right
side of the machine. Press down on the brake
pedal to activate the rear brake.
EC158001
FUEL COCK
The fuel cock supplies fuel from the tank to
carburetor while filtering the fuel. The fuel cock
has the two positions:
OFF: With the lever in this position, fuel will not
flow. Always return the lever to this posi-
tion when the engine is not running.
ON: With the lever in this position, fuel flows
to the carburetor. Normal riding is done
with the lever in this position.
COLD STARTER KNOB
When cold, the engine requires a richer air-fuel
mixture for starting. A separate starter circuit,
which is controlled by the cold starter knob 1,
supplies this mixture. Pull the cold starter knob
out to open the circuit for starting. When the
engine has warmed up, push it in to close the
circuit.
1
HOT STARTER LEVER
The hot starter lever 1 is used when starting a
warm engine.
Use the hot starter lever when starting the
engine again immediately after it was stopped
(the engine is still warm). Pulling the hot starter
lever injects secondary air to thin the air-fuel
mixture temporarily, allowing the engine to be
started more easily.

1 - 19
GEN
INFO
CLEANING AND STORAGE
EC1B0000
CLEANING AND STORAGE
EC1B1000
CLEANING
Frequent cleaning of your machine will
enhance its appearance, maintain good overall
performance, and extend the life of many com-
ponents.
1. Before washing the machine, block off the
end of the exhaust pipe to prevent water
from entering. A plastic bag secured with a
rubber band may be used for this purpose.
2. If the engine is excessively greasy, apply
some degreaser to it with a paint brush. Do
not apply degreaser to the chain, sprock-
ets, or wheel axles.
3. Rinse the dirt and degreaser off with a gar-
den hose; use only enough pressure to do
the job.
CAUTION:
Excessive hose pressure may cause water
seepage and contamination of wheel bear-
ings, front forks, brakes and transmission
seals. Many expensive repair bills have
resulted from improper high pressure
detergent applications such as those avail-
able in coin-operated car washers.
4. After the majority of the dirt has been
hosed off, wash all surfaces with warm
water and a mild detergent. Use an old
toothbrush to clean hard-to-reach places.
5. Rinse the machine off immediately with
clean water, and dry all surfaces with a soft
towel or cloth.
6. Immediately after washing, remove excess
water from the chain with a paper towel
and lubricate the chain to prevent rust.
7. Clean the seat with a vinyl upholstery
cleaner to keep the cover pliable and
glossy.

3 - 5
INSP
ADJ
EC350000
ENGINE
EC351011
COOLANT LEVEL INSPECTION
WARNING
Do not remove the radiator cap
1, drain
bolt and hoses when the engine and radia-
tor are hot. Scalding hot fluid and steam
may be blown out under pressure, which
could cause serious injury.
When the engine has cooled, place a thick
towel over the radiator cap, slowly rotate
the cap counterclockwise to the detent.
This procedure allows any residual pres-
sure to escape. When the hissing sound
has stopped, press down on the cap while
turning counterclockwise and remove it.
CAUTION:
Hard water or salt water is harmful to the
engine parts. You may use distilled water, if
you can’t get soft water.
1. Place the machine on a level place, and
hold it in an upright position.
2. Remove:
Radiator cap
3. Check:
Coolant level a
Coolant level low → Add coolant.
1Radiator
ENGINE/COOLANT LEVEL INSPECTION

3 - 24
INSP
ADJ
CHASSIS/BRAKE SYSTEM AIR BLEEDING
EC360000
CHASSIS
EC361012
BRAKE SYSTEM AIR BLEEDING
WARNING
Bleed the brake system if:
The system has been disassembled.
A brake hose has been loosened or
removed.
The brake fluid is very low.
The brake operation is faulty.
A dangerous loss of braking performance
may occur if the brake system is not prop-
erly bled.
1. Remove:
Master cylinder cap
Diaphragm
Reservoir float (front brake)
Protector (rear brake)
2. Bleed:
Brake fluid
ÈFront
ÉRear
Air bleeding steps:
a. Add proper brake fluid to the reservoir.
b. Install the diaphragm. Be careful not to
spill any fluid or allow the reservoir to
overflow.
c. Connect the clear plastic tube 2 tightly
to the caliper bleed screw 1.
d. Place the other end of the tube into a
container.
e. Slowly apply the brake lever or pedal
several times.
f. Pull the lever in or push down on the
pedal. Hold the lever or pedal in position.
g. Loosen the bleed screw and allow the
lever or pedal to travel towards its limit.
h. Tighten the bleed screw when the lever
or pedal limit has been reached; then
release the lever or pedal.
T R..
Bleed screw:
6 Nm (0.6 m  kg, 4.3 ft  lb)
i. Repeat steps (e) to (h) until of the air
bubbles have been removed from the
system.
È
É

4 - 5
ENG
ASSEMBLY AND INSTALLATION
Exhaust pipe and silencer
1. Install:
Gasket
Exhaust pipe 1
Nut (exhaust pipe) 2
Bolt (exhaust pipe) 3
NOTE:
First, temporarily tighten the nut (exhaust pipe),
then tighten the bolt (exhaust pipe) 20 Nm
(2.0 mkg, 14 ftlb). After that, retighten the
nut (exhaust pipe) 13 Nm (1.3 mkg, 9.4 ftlb)
and then the bolt (exhaust pipe) 24 Nm
(2.4 mkg, 17 ftlb).
3
1 2New
T R..13 Nm (1.3 m · kg, 9.4 ft · lb)
T R..24 Nm (2.4 m · kg, 17 ft · lb)
2. Install:
Clamp 1
Gasket 2
Silencer 3
Plain washer 4
Bolt (silencer) 5
NOTE:
Install the gasket with its meshed area a
toward the exhaust pipe side.
The gasket should be installed according to
the dimension shown.
4
5
13
2Newa
2.5 ~ 3.5 mm (0.10 ~ 0.14 in)
T R..16 Nm (1.6 m · kg, 11 ft · lb)
New
T R..35 Nm (3.5 m · kg, 25 ft · lb)
EXHAUST PIPE AND SILENCER

4 - 7
ENGRADIATOR
EC456000
HANDLING NOTE
WARNING
Do not remove the radiator cap when the
engine and radiator are hot. Scalding hot
fluid and steam may be blown out under
pressure, which could cause serious
injury.
When the engine has cooled, open the radi-
ator cap by the following procedure:
Place a thick rag, like a towel, over the radi-
ator cap, slowly rotate the cap counter-
clockwise to the detent. This procedure
allows any residual pressure to escape.
When the hissing sound has stopped,
press down on the cap while turning coun-
terclockwise and remove it.
EC454000
INSPECTION
EC444100
Radiator
1. Inspect:
Radiator core 1
Obstruction → Blow out with compressed
air through rear of the radiator.
Bent fin → Repair/replace.
EC455000
ASSEMBLY AND INSTALLATION
Radiator
1. Install:
Pipe 1 1
Hose 1 2
Pipe 2 3
Hose 3 4
Hose 4 5
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
2. Install:
Hose 2 1
Radiator (left) 2
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

4 - 77
ENG
5. Hook:
Torsion spring 1
NOTE:
Turn the torsion spring clockwise and hook
into the proper hole a in the crankcase.
Kick idle gear
1. Install:
Kick idle gear 1
Plain washer 2
Circlip 3
NOTE:
Install the kick idle gear with its depressed
side a toward you.
Apply the engine oil on the kick idle gear
inner circumference.
New
KICK AXLE AND SHIFT SHAFT

7 - 11
TUN
EC720000
CHASSIS
EC71P002
Selection of the secondary reduction ratio
(Sprocket)
reduction ratio>
•It is generally said that the secondary gear
ratio should be reduced for a longer straight
portion of a speed course and should be
increased for a course with many corners.
Actually, however, as the speed depends on
the ground condition of the day of the race,
be sure to run through the circuit to set the
machine suitable for the entire course.
•In actuality, it is very difficult to achieve set-
tings suitable for the entire course and some
settings may be sacrificed. Thus, the settings
should be matched to the portion of the
course that has the greatest effect on the
race result. In such a case, run through the
entire course while making notes of lap times
to find the best balance; then, determine the
secondary reduction ratio.
•If a course has a long straight portion where
a machine can run at maximum speed, the
machine is generally set such that it can
develop its maximum revolutions toward the
end of the straight line, with care taken to
avoid the engine over-revving.
NOTE:
Riding technique varies from rider to rider and
the performance of a machine also vary from
machine to machine. Therefore, do not imitate
other rider’s settings from the beginning but
choose your own setting according to the level
of your riding technique. Secondary
reduction
ratio=Number of driven sprocket teeth
Number of drive sprocket teeth
Standard secondary
reduction ratio49/13 (3.769)
SETTING

7 - 20
TUNSETTING
EC72H002
Suspension setting
•Front fork
NOTE:
•If any of the following symptoms is experienced with the standard position as the base, make
resetting by reference to the adjustment procedure given in the same chart.
•Before any change, set the rear shock absorber sunken length to the standard figure 90 ~ 100 mm
(3.5 ~ 3.9 in).
SymptomSection
Check Adjust
JumpLarge
gapMedium
gapSmall
gap
Stiff over entire rangeCompression damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Oil amount Decrease oil amount by about 5 ~ 10 cm
3 (0.2 ~
0.4 Imp oz, 0.2 ~ 0.3 US oz).
Spring Replace with soft spring.
Unsmooth movement
over entire rangeOuter tube Check for any bends, dents, and other noticeable
scars, etc. If any, replace affected parts.
Inner tube
Slide metal Replace with a new one for extended use.
Piston metal Replace with a new one for extended use.
Under bracket tightening
torqueRetighten to specified torque.
Poor initial
movementRebound damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Oil seal Apply grease in oil seal wall.
Soft over entire
range, bottoming outCompression damping Turn adjuster clockwise (about 2 clicks) to increase
damping.
Oil amount Increase oil amount by about 5 ~ 10 cm
3 (0.2 ~
0.4 Imp oz, 0.2 ~ 0.3 US oz).
Spring Replace with stiff spring.
Stiff toward stroke
endOil amountDecrease oil amount by about 5 cm
3 (0.2 Imp oz,
0.2 US oz).
Soft toward stroke
end, bottoming outOil amountIncrease oil amount by about 5 cm
3 (0.2 Imp oz,
0.2 US oz).
Stiff initial movement Compression dampingTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Low front, tending to
lower front postureCompression damping Turn adjuster clockwise (about 2 clicks) to increase
damping.
Rebound damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Balance with rear end Set sunken length for 95 ~ 100 mm (3.7 ~ 3.9 in) when
one passenger is astride seat (lower rear posture).
Oil amount Increase oil amount by about 5 cm
3 (0.2 Imp oz,
0.2 US oz).
“Obtrusive” front,
tending to upper front
postureCompression damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Balance with rear end Set sunken length for 90 ~ 95 mm (3.5 ~ 3.7 in)
when one passenger is astride seat (upper rear pos-
ture).
Spring Replace with soft spring.
Oil amount Decrease oil amount by about 5 ~ 10 cm
3 (0.2 ~
0.4 Imp oz, 0.2 ~ 0.3 US oz).