YAMAHA YFZ450R 2021 Repair Manual

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EBU20907Parking on a slope
WARNING
EWB00852Avoid parking on hills or other inclines. Parking
on a hill or other incline could cause the ATV to
roll out of control, increasing the chance of an
accident. If you must park on an incline, place
the ATV transversely across the incline, shift
into first gear, stop the engine, apply the park-
ing brake, and then block the front and rear
wheels with rocks or other objects.Never park the ATV on hills that are too steep
to walk up easily.
1. Bring the ATV to a stop by applying the
brakes.
2. With the brake pedal applied, shift into first gear and then stop the engine.
3. Apply the parking brake.EBU20911Accessories and loadingEBU20922Genuine Yamaha Accessories
Choosing accessories for your ATV is an impor-
tant decision. Genuine Yamaha Accessories,
which are available only from a Yamaha dealer,
1. Parking brake lever (locked position)UBKD60E0.book Page 5 Wednesday, November 18, 2020 8:39 AM

7-6
7have been designed, tested, and approved by
Yamaha for use on your ATV. Many companies with no connection to Yamaha manufacture parts
and accessories or offer other modifications for
Yamaha vehicles. Yamaha is not in a position to test the products that these aftermarket compa-
nies produce. Therefore, Yamaha can neither en-
dorse nor recommend the use of accessories not
sold by Yamaha or modifications not specifically
recommended by Yamaha, even if sold and in-
stalled by a Yamaha dealer.
Aftermarket parts, accessories, and modifica-
tions
While you may find aftermarket products similar in
design and quality to genuine Yamaha Accesso-
ries, recognize that some aftermarket accessories
or modifications are not suitable because of po-
tential safety hazards to you or others. Installing
aftermarket products or having other modifica-
tions performed to your ATV that change any of
the vehicle’s design or operation characteristics
can put you and others at greater risk of serious
injury or death. You are responsible for injuries re-
lated to changes in the vehicle. Keep the following in mind when considering an
accessory or operating an ATV which has acces-
sories.

Accessories should be rigidly and securely
mounted. An accessory which can shift position
or come off while you are riding could affect
your ability to control the ATV.
 Do not mount an accessory where it could inter-
fere with your ability to control the ATV. Exam-
ples include (but are not limited to) a heavy or
bulky object attached to the handlebars which
could make steering difficult, an accessory that
limits your ability to move around on the seat, or
one that limits your view.
 Use extra caution when riding an ATV with ac-
cessories. The ATV may handle differently than
it does without accessories.
EBU20942Loading
WARNING
EWB00821Never exceed the stated load capacity for this
ATV. Overloading this ATV or carrying or tow-
ing cargo improperly could cause changes in
ATV handling which could lead to an accident.
Cargo should be properly distributed and se-
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curely attached. Reduce speed when carrying
cargo or pulling a trailer. Allow greater dis-
tance for braking.
As originally equipped, this ATV is not designed to
carry cargo or tow a trailer. If you choose to add
accessories so that you can carry cargo or tow a
trailer, you must use common sense and good
judgment as the stability and handling of an ATV
can be changed. When adding accessories, keep
the following points in mind:

Never exceed the weight limits shown. An over-
loaded ATV can be unstable.
 If you are carrying cargo and towing a trailer, in-
clude the tongue weight in the maximum ATV
load limit.
 Load cargo on the carriers as close to the center
of the ATV as possible. Put cargo at the rear of
the front carrier, at the front of the rear carrier,
and center it. 
Tie down cargo securely to the carriers. Make
sure cargo in the trailer cannot move around. A
shifting load can cause an accident.
 Make sure the load does not interfere with con-
trols or your ability to see where you are going.
 Ride more slowly than you would without a
load. The more weight you carry, the slower you
should go. Although conditions vary, it is good
practice not to exceed 2nd gear whenever you
are carrying heavier loads or when towing a
trailer.
 Allow more braking distance. A heavier ATV
takes longer to stop.
 Avoid making sharp turns unless at very slow
speeds.
 Avoid hills and rough terrain. Choose terrain
carefully. Added weight affects the stability and
handling of the ATV.
MAXIMUM LOADING LIMIT
ATV loading limit (total weight of rider, car-
go, accessories, and tongue):100.0 kg (220 lb)UBKD60E0.book Page 7 Wednesday, November 18, 2020 8:39 AM

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EBU21142
RIDING YOUR ATV
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EBU21619GETTING TO KNOW YOUR ATV
This ATV is intended for recreational use by expe-
rienced operators only. This section, Riding your
ATV, provides general ATV riding instructions for
recreational riding. The skills and techniques de-
scribed in this section, however, are appropriate
for all types of riding. Riding your ATV requires
special skills acquired through practice over a pe-
riod of time. Take the time to learn the basic tech-
niques well before attempting more difficult
maneuvers.
Riding your new ATV can be a very enjoyable ac-
tivity, providing you with hours of pleasure. But it
is essential to familiarize yourself with the opera-
tion of the ATV to achieve the skill necessary to
enjoy riding safely. Before you begin to ride, be
sure you have read this Owner’s Manual com-
pletely and understand the operation of the con-
trols. Pay particular attention to the safety
information on pages 3-1–3-6. Also read all warn-
ing and notice labels on your ATV.RIDE WITH CARE AND GOOD JUDGMENT
Get training if you are inexperienced.
WARNING
EWB01382
Do not operate this ATV or allow anyone else
to operate it without proper instruction. The
risk of an accident is greatly increased if the
operator does not know how to operate the
ATV properly in different situations and on
different types of terrain.
 Do not operate this ATV at speeds too fast
for your skills or the conditions, as this in-
creases your chances of losing control of the
ATV and an accident. Always go at a speed
that is proper for the terrain, visibility and op-
erating conditions, and your experience. Beginning and inexperienced operators should
regularly practice the skills and the operating
techniques described in this Owner’s Manual.
Riding your ATV requires skills acquired
through practice over a period of time.
Do not attempt to operate at maximum perfor-
mance until you are totally familiar with the ATV’s
handling and performance characteristics. Take
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8the time to learn the basic techniques well before
attempting more difficult maneuvers. Become fa-
miliar with this ATV at slow speeds first, even if you
are an experienced operator.
Not recommended for children under 16 years
of age.
WARNING
EWB01391A child under 16 should never operate an ATV
with engine size greater than 90 cc. Use by
children 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 the operator only
– passengers prohibited.
The long seat is to allow the operator to shift posi-
tion as needed during operation. It is not for carry-
ing passengers.
WARNING! Never carry a
passenger. Carrying a passenger on this ATV
greatly reduces your ability to balance and
control this ATV. You could have an accident,
resulting in severe injury or death to you and/or
your passenger.
[EWB01402]
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Apparel
Always wear the following to reduce risk of injury
in an accident:

Approved motorcycle helmet that fits properly
 Eye protection (goggles, helmet face shield, or
protective eyewear)
 Over-the-ankle boots, gloves, long-sleeved
shirt or jacket, and long pants
An approved helmet and other personal protective
equipment can reduce the severity of injuries in an
accident. WARNING! Operating without an ap-
proved motorcycle helmet increases your
chances of a severe head injury or death in the
event of an accident.
[EWB01412]
Wear eye protection when operating your ATV to
reduce the risk of a serious accident or injury. Eye
protection, such as a face shield or goggles, may
reduce the risk of foreign material getting in your
eyes and help prevent loss of vision. WARNING!
Operating without eye protection can result in
an accident and increases your chances of a
severe injury in the event of an accident.[EWB02612]
Do not operate after or while consuming alco-
hol or drugs.
The operator’s performance capability is reduced
by the influence of alcohol or drugs. Consuming
alcohol or drugs could seriously affect your judg-
ment, cause you to react more slowly, and affect
your balance and perception. WARNING! Never
consume alcohol or drugs before or while driv-
ing this ATV. You increase your chance of an
accident.
[EWB01422]
1. Protective clothing
2. Goggles
3. Gloves
4. Boots
5. Helmet
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8Pre-operation checks
Always inspect your ATV each time you use it to
make sure the ATV is in safe operating condition.
Perform the pre-operation checks listed on page
6-1. Always follow the inspection and mainte-
nance procedures and schedules described in the
Owner’s Manual.
WARNING! Failure to inspect
the ATV before riding it or failure to maintain it
properly increases the possibility of an acci-
dent and equipment damage.
[EWB01433]
Speed limiter
For riders less experienced with this model, the
throttle lever housing is equipped with a speed
limiter. 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 decreases the maximum speed of the ATV.
Turning in the adjusting screw decreases top
speed, and turning it out increases top speed.
(See page 5-4.)
Loading and accessories
WARNING
EWB00973Improper loading or towing can increase the
risk of loss of control, an overturn, or other ac-
cident. To reduce the risk of an accident:1. Adjusting screw
2. Locknut
2
1
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
Do not exceed the maximum loading limits
for the vehicle (see “MAXIMUM LOADING
LIMIT” below or vehicle labeling).
 Make sure the load does not interfere with
your control or ability to see where you are
going.
 Reduce speed and allow more room to stop.
A heavier vehicle takes longer to stop.
 Avoid hills and rough terrain. Choose terrain
carefully. Use extreme caution when towing
or carrying a load on inclines.
 Turn gradually and go slowly.
As originally equipped, this ATV is not designed to
carry cargo or tow a trailer. If you choose to add
accessories to carry cargo, you must use com-
mon 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. During operation
Always keep your feet on the footrests during op-
eration; otherwise, they may contact the rear
wheels.
WARNING! 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
footrest, your foot or leg may come into con-
tact with the rear wheels, which could injure
you or cause an accident.
[EWB02661]
MAXIMUM LOADING LIMIT ATV loading limit (total weight of cargo, rid-
er, accessories, and tongue):100.0 kg (220 lb)
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8Avoid wheelies and jumping.
WARNING! At-
tempting wheelies, jumps, and other stunts in-
creases the chance of an accident, including
an overturn. Never attempt stunts, such as
wheelies or jumps. Don’t try to show off.
[EWB01482]Modifications and accessories
Never modify this ATV through improper installa-
tion or use of accessories or other modification. All
parts and accessories added to this ATV should
be genuine Yamaha or equivalent components
designed for use on this ATV and should be in-
stalled and used according to instructions. If you have questions, consult an authorized ATV dealer.
WARNING! Operating this ATV with improper modifications may cause changes in handling
which in some situations could lead to an acci-
dent.
[EWB01492]
Exhaust system
WARNING
EWB01502 Dry grass or brush or other combustible ma-
terial accumulated around the engine area
could catch fire. Do not operate, idle, or park
the ATV in dry grass or other dry ground cov-
er. Keep the engine area free of dry grass,
brush, or other combustible material.
 Someone touching the exhaust system dur-
ing or after operation could be burned. Do
not touch the hot exhaust system. Do not
park the ATV in a place where others might
be likely to touch it. The muffler and other engine parts become ex-
tremely hot during operation and remain hot after
the engine has stopped. To reduce the risk of fire
during operation or after leaving the ATV, do not
let brush, grass and other materials collect under
the vehicle, near the muffler or exhaust pipe, or
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