YAMAHA YFZ450 2009 Repair Manual

7-3
1
2
3
4
5
67
8
9
10
11

with engine size greater than 90 cc. Use by chil-
dren of ATVs that are not recommended for
their age can lead to severe injury or death of
the child.
This ATV is designed to carry operator only –
passengers prohibited.
WARNING

EWB01400
Never carry a passenger. The long seat is to al-
low the operator to shift position as needed
during operation. It is not for carrying passen-
gers. Carrying a passenger on this ATV greatly
reduces your ability to balance and control this
ATV. It could cause an accident, resulting in
harm to you and/or your passenger.
Apparel
Always wear an approved motorcycle helmet that
fits properly.
You should also wear:

eye protection (goggles or face shield)

gloves

boots

long-sleeved shirt or jacket

long pants

7-4
1
2
3
4
5
67
8
9
10
11
WARNING

EWB01410
Never operate this ATV without wearing an ap-
proved motorcycle helmet, eye protection and
protective clothing. Operating without an ap-
proved motorcycle helmet increases your
chances of a severe head injury or death in the
event of an accident. Operating without eye
protection can result in an accident and in-
creases your chances of a severe injury in theevent of an accident. Operating without protec-
tive clothing increases your chances of severe
injury in the event of an accident.
Do not operate after consuming alcohol or
drugs.
The operator’s performance capability is reduced
by the influence of alcohol or drugs.WARNING
EWB01420
Never consume alcohol or drugs before or
while driving this ATV.
Pre-operation checks
Always perform the pre-operation checks listed on
1. Protective clothing
2. Goggles
3. Gloves
4. Boots
5. Helmet

7-5
1
2
3
4
5
67
8
9
10
11

page 5-1 before riding for proper care of the ATV
and to ensure safety.
WARNING

EWB01430
Always inspect your ATV each time you use it
to make sure the ATV is in safe operating con-
dition. Always follow the inspection and main-
tenance procedures and schedules described
in the Owner’s Manual. Failure to inspect the
ATV before operating or failure to properly
maintain the ATV increases the possibility of
an accident or equipment damage.
WARNING

EWB01440
Always use the size and type tires specified in
the Owner’s Manual for this ATV on page 5-4.
Always maintain proper tire pressure as de-
scribed in the Owner’s Manual on page 5-5.
Use of improper tires on this ATV, or operation
of this ATV with improper or uneven tire pres-
sure, may cause loss of control, increasing
your risk of an accident.Do not operate at speeds too fast for your
skills or the conditions.WARNING

EWB01450
Always go at a speed that is proper for the ter-
rain, visibility and operating conditions, and
your experience. Operating this ATV at speeds
too fast for your skills or the conditions in-
creases your chances of losing control of the
ATV, which can result in an accident.
Speed limiter
For riders less experienced with this model, the
throttle lever housing is equipped with a speed lim-
iter. The speed limiter keeps the throttle from fully
opening, even when the throttle lever is pushed to
the maximum. Turning in the adjusting screw limits
the maximum engine power available and de-
creases the maximum speed of the ATV. Turning
in the adjusting screw decreases top speed, and
turning it out increases top speed. (See page 4-4.)

7-6
1
2
3
4
5
67
8
9
10
11

Loading and accessories
As originally equipped, this ATV is not designed to
carry cargo or tow a trailer. If you choose to add ac-
cessories so that you can carry cargo or tow a trail-
er, you must use common sense and good
judgment.
Use extra caution when riding the ATV with addi-
tional loads, such as accessories or cargo. The
ATV’s handling may be adversely affected. Re-
duce your speed when adding additional loads.WARNING
EWB01460

Never exceed the stated load capacity for
this ATV.

Cargo should be properly distributed and se-
curely attached.

Reduce speed when carrying cargo or pull-
ing a trailer. Allow greater distance for brak-
ing.

Always follow the instructions in your Own-
er’s Manual for carrying cargo or pulling a
trailer.
During operation
Always keep your feet on the footboards during op-
eration, otherwise they may contact the rear
wheels.
1. Adjusting screw
2. Locknut
2
1

MAXIMUM LOADING LIMIT
ATV loading limit (total weight of cargo, rider,
accessories, and tongue):
100.0 kg (220 lb)

7-7
1
2
3
4
5
67
8
9
10
11
WARNING

EWB01470
Always keep both hands on the handlebars
and both feet on the footboards of your ATV
during operation. Removing even one hand or
foot can reduce your ability to control the ATV
or could cause you to lose your balance and
fall off of the ATV. If you remove a foot from a
footboard, your foot or leg may come into con-
tact with the rear wheels, which could injure
you or cause an accident.
Avoid wheelies and jumping. You may lose control
of the ATV or overturn.WARNING
EWB01480
Never attempt stunts, such as wheelies or
jumps. Don’t try to show off.
ModificationsWARNING

EWB01490
Never modify this ATV through improper in-
stallation or use of accessories. All parts and
accessories added to this ATV should be gen-
uine Yamaha or equivalent components de-

7-8
1
2
3
4
5
67
8
9
10
11

signed for use on this ATV and should be
installed and used according to instructions.
Improper installation of accessories or modifi-
cation of this ATV may cause changes in han-
dling which in some situations could lead to an
accident. If you have questions, consult an au-
thorized ATV dealer.
Exhaust system
The exhaust system on the ATV is very hot during
and following operation. To prevent burns, avoid
touching the exhaust system. Park the ATV in a
place where pedestrians or children are not likely
to touch it. Also, avoid parking in or around dry
grass, brush or other combustible materials to pre-
vent causing a fire hazard.
WARNING

EWB01500

Do not touch the hot exhaust system.

Do not park the ATV during or after operation
in a place where others might be likely to
touch it.

Do not operate, idle, or park the ATV in dry
grass, dry ground cover, or combustible ma-
terials.BE CAREFUL WHERE YOU RIDE
This ATV is designed for use on unpaved surfaces
only. Riding on paved surfaces can cause loss of
control.
WARNING

EWB01510
Always avoid paved surfaces, including side-
walks, driveways, parking lots and streets.
ATVs are designed for use on unpaved surfac-
es only. Paved surfaces may seriously affect
handling and control of the ATV, and may
cause the ATV to go out of control.

7-9
1
2
3
4
5
67
8
9
10
11

While riding on unpaved public streets or roads
may be legal in your area, such operation can in-
crease the risk of collision with other vehicles.
Watch carefully for other vehicles. Make sure you
know your country’s laws and regulations before
you ride on unpaved public streets or roads. Do not
ride on any paved public street, road or motorway.
WARNING

EWB01520
Never operate this ATV on any paved street,paved road or motorway. You can collide with
another vehicle. In many areas, it is illegal to
operate ATVs on public streets, roads and
highways.
Know the terrain where you ride. Ride cautiously in
unfamiliar areas. Stay alert for
holes, rocks, or
roots
in the terrain, and
other hidden hazards
which may cause the ATV to upset.WARNING

EWB01530
Go slowly and be extra careful when operating

7-10
1
2
3
4
5
67
8
9
10
11

on unfamiliar terrain. Always be alert to chang-
ing terrain conditions when operating the ATV.
WARNING

EWB01540
Do not operate on excessively rough, slippery
or loose terrain until you have learned and
practiced the skills necessary to control the
ATV on such terrain. Failure to use extra care
when operating on excessively rough, slippery
or loose terrain could cause loss of traction or
ATV control, which could result in an accident,
including an overturn.
When riding in an area where you might not easily
be seen, such as desert terrain, mount a caution
flag on the ATV. DO NOT use the flag pole bracket
as a trailer hitch.

7-11
1
2
3
4
5
67
8
9
10
11
WARNING

EWB01550
Always mount a caution flag on the ATV to
make you more visible when operating in areas
where you might not be seen by other vehicles.
Watch carefully for other vehicles.
Do not ride in areas posted “no trespassing”.
Do not ride on private property without getting per-
mission.Select a large, flat, unpaved area to become famil-
iar with your ATV. Make sure that this area is free
of obstacles and other riders. You should practice
control of the throttle, brakes, shifting procedures,
and turning techniques in this area before trying
more difficult terrain. Always avoid riding on paved
surfaces: the ATV is designed for use on unpaved
surfaces only, and handling maneuvers are more
difficult to perform on pavement.
Set the parking brake and follow the instruction on
page 6-1 to start the engine. Once it has warmed
up you are ready to begin riding your ATV. As you
get on the ATV, be sure not to accidentally move
the shift pedal. Remember that the engine and ex-
haust pipe will be hot when riding and afterwards;
do not allow skin or clothing to come in contact with

7-12
1
2
3
4
5
67
8
9
10
11

these components.
With the engine idling, pull the clutch lever to dis-
engage the clutch and shift into 1st gear, and then
release the parking brake. Open the throttle grad-
ually, and at the same time, release the clutch le-
ver slowly. Once the ATV has attained adequate
speed, release the throttle lever and at the same
time, quickly pull in the clutch lever and shift into
2nd gear. Open the throttle part way and gradually
release the clutch. Use this same procedure as
you move into the higher gears. Be sure to coordi-
nate the use of the throttle and shift pedal properly.
If the throttle is applied too abruptly or if the throttle
is not released during shifting, or if the shift pedal
is not released before applying the throttle, the
front wheels may lift off the ground, resulting in a
loss of directional control. Avoid higher speeds un-
til you are thoroughly familiar with the operation of
your ATV.
WARNING

EWB01720
Always open the throttle gradually and release
the clutch lever slowly. Otherwise, the ATV
could wheelie which would increase the
chance of an accident.
NOTICE

ECB00230
Do not shift gears without releasing the throt-
tle. Damage to the engine or drive train may oc-
cur.
When slowing down or stopping, release the throt-
tle and apply the brakes smoothly and evenly. As
you slow down, shift to a lower gear. Be sure that
the engine has sufficiently slowed before engaging
a lower gear. Improper use of the brakes or shifting
can cause the tires to lose traction, reducing con-
trol and increasing the possibility of an accident.
WARNING

EWB01560
Make sure the engine has sufficiently slowed
before shifting to a lower gear. Engaging a low-
er gear when the engine speed is too high
could cause the wheels to stop rotating.
TURNING YOUR ATV
To achieve maximum traction on unpaved surfac-
es, the two rear wheels are mounted solidly on one
axle and turn together at the same speed. There-
fore, unless the wheel on the inside of the turn is al-
lowed to slip or lose some traction, the ATV will
resist turning. A special turning technique must be