Page 5 of 120

INTRODUCTION
Congratulations on your purchase of the Yamaha YFM90RY. This ATV represents the result of many years
of Yamaha experience in the production of fine sporting, touring, and pacesetting racing machines. With the
purchase of this Yamaha, you can now appreciate the high degree of craftsmanship and reliability that have
made Yamaha a leader in these fields.
This manual will provide you with a good basic understanding of the features and operation of this ATV.
This manual includes important safety information. It provides information about special tech-
niques and skills necessary to ride the ATV. It also includes basic maintenance and inspection proce-
dures. If you have any questions regarding the operation or maintenance of your ATV, please consult a
Yamaha dealer.
AN IMPORTANT SAFETY MESSAGE:READ THIS MANUAL COMPLETELY BEFORE OPERATING YOUR ATV. MAKE SURE YOU
UNDERSTAND ALL INSTRUCTIONS.PAY CLOSE ATTENTION TO THE WARNING AND NOTICE LABELS ON THE ATV.THIS ATV, AND ANY OTHER ATV OVER 70 cc, SHOULD NOT BE OPERATED BY A CHILD UNDER
12 YEARS OF AGE.
AN IMPORTANT NOTE TO PARENTS:
This ATV is not a toy. Before you let your child ride this ATV, you should understand the instructions and
warnings in this Owner’s Manual. Then be sure your child understands and will follow them. Children differ
Page 7 of 120
WARNING
N O T I C ETIPThis is the safety alert symbol. It is used to alert you to potential
personal injury hazards. Obey all safety messages that follow this
symbol to avoid possible injury or death.
damage to the vehicle or other property.
A TIP provides key information to make procedures easier or clearer.
A WARNING indicates a hazardous situation which, if not avoided,
could result in death or serious injury. A NOTICE indicates special precautions that must be taken to avoid
IMPORTANT MANUAL INFORMATION
FAILURE TO FOLLOW THE WARNINGS CONTAINED IN THIS MANUAL CAN RESULT IN SERIOUS IN-
JURY OR DEATH.
Particularly important information is distinguished in this manual by the following notations:
* Product and specifications are subject to change without notice.
Page 9 of 120

TABLE OF CONTENTS
SAFETY INFORMATION..............................1-1
LOCATION OF THE WARNING AND
SPECIFICATION LABELS............................2-1DESCRIPTION ..............................................3-1 Left view.....................................................3-1Right view...................................................3-1
Controls and instruments...........................3-2
INSTRUMENT AND CONTROL
FUNCTIONS..................................................4-1 Main switch...............................................4-1
Handlebar switches ................................... 4-2
Throttle lever ............................................. 4-3
Speed limiters............................................. 4-3
Front brake lever ........................................ 4-6
Rear brake lever ....................................... 4-6
Parking brake ............................................ 4-7
Fuel tank cap ............................................ 4-8 Fuel ........................................................... 4-8
Fuel cock .............................................. 4-10
Choke ..................................................... 4-11
Seat ........................................................ 4-11
PRE-OPERATION CHECKS.........................5-1 Pre-operation check list............................5-1
Fuel ........................................................... 5-3
Engine oil .................................................. 5-3
Final transmission oil ................................ 5-3
Front and rear brakes ............................... 5-3
Throttle lever ............................................. 5-4
Tires .......................................................... 5-4
Measuring the tire pressure ...................... 5-5
Tire wear limit ........................................... 5-6
Chassis fasteners ..................................... 5-7
Instruments and switches ......................... 5-7
OPERATION................................................6-1 Starting a cold engine ............................... 6-1
Starting a warm engine ............................. 6-3
Engine break-in ........................................ 6-4
Parking ..................................................... 6-4
Parking on a slope ................................... 6-5
Accessories and loading .......................... 6-6
Vehicle speed limiter ................................. 4-4
Engine speed limiter plate.......................... 4-5 Kick starter
............................................. 4-12
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1-3
1
Avoid crossing the side of a steep hill if possible.Always use proper procedures if you stall or roll
backwards when climbing a hill. To avoid stall-
ing, use the proper gear and maintain a steady
speed when climbing a hill. If you stall or roll
backwards, follow the special procedure for
braking described in this manual. Dismount on
the uphill side or to a side if pointed straight up-
hill. Turn the ATV around and remount, following
the procedure described in this manual.Always check for obstacles before operating in a
new area.Never attempt to operate over large obstacles,
such as large rocks or fallen trees. Always follow
proper procedures when operating over obsta-
cles as described in this manual.Always be careful when skidding or sliding.
Learn to safely control skidding or sliding by
practicing at low speeds and on level, smooth
terrain. On extremely slippery surfaces, such as
ice, go slowly and be very cautious in order to re-
duce the chance of skidding or sliding out of con-
trol.Never operate an ATV in fast flowing water or in
water deeper than that recommended in this
manual. Remember that wet brakes may havereduced stopping ability. Test your brakes after
leaving water. If necessary, apply them several
times to let friction dry out the linings.
Always use the size and type of tires specified in
this manual.Always maintain proper tire pressure as de-
scribed in this manual.Never modify an ATV through improper installa-
tion or use of accessories.Never exceed the stated load capacity for an
ATV. Cargo should be properly distributed and
securely attached. Reduce speed and follow in-
structions in this manual for carrying cargo or
pulling a trailer. Allow greater distance for brak-
ing.
WARNING
Always turn off the engine when refueling.Do not refuel right after the engine has been
running and is still very hot.Do not spill gasoline on the engine or ex-
haust pipe/muffler when refueling. Never re-
fuel while smoking, or in the vicinity of
sparks, open flames, or other sources of ig-
nition such as the pilot lights of water heat-
ers and clothes dryers. Gasoline can catch
Page 15 of 120
1-4
1
fire and you could be burned.When transporting the ATV in another vehi-
cle, be sure it is kept upright and that the fuel
cock is in the “OFF” position. Otherwise, fuel
may leak out of the carburetor or fuel tank.Gasoline is poisonous. If you should swal-
low some gasoline or inhale a lot of gasoline
vapor, or get some gasoline in your eyes,
seek medical help immediately. If gasoline
spills on your skin, wash with soap and wa-
ter. If gasoline spills on your clothing,change your clothes.
WARNING
Always operate your ATV in an area with ade-
quate ventilation. Never start or run the engine
in a closed area. Exhaust fumes are poisonous
and may cause loss of consciousness and
death within a short time.
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2-1
LOCATION OF THE WARNING AND SPECIFICATION LABELS
Read and understand all of the labels on your ATV. These labels contain important information for safe and
proper operation.
Never remove any labels from your ATV. If a label becomes difficult to read or comes off, request a replace-
ment label from your Yamaha dealer.
2
23
4 51
6
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4-3
4
Throttle lever Once the engine is running, movement of the throt-
tle lever will increase the engine speed.
Regulate the speed of the ATV by varying the
throttle position. Because the throttle is spring-
loaded, the ATV will decelerate, and the engine will
return to an idle any time the hand is removed from
the throttle lever.
Before starting the engine, check the throttle to be
sure it is operating smoothly. Make sure it returns
to the idle position as soon as the lever is released.
Speed limitersYour ATV was delivered with two speed limiter
devices. A vehicle speed limiter adjusting screw
and a removable engine speed limiter plate.
Yamaha recommends that all beginning riders start
off with the vehicle speed limiter adjusting screw fully
turned in and the engine speed limiter plate installed
to limit the amount of speed available while they learn.
1. Throttle lever
1
WARNING
Malfunction of the throttle could make it diffi-
cult to speed up or slow down when you need
to. This could cause an accident. Check the op-
eration of the throttle lever before you start the
engine. If the throttle does not work smoothly,
check for the cause. Correct the problem be-fore riding the ATV or consult a Yamaha dealer.
Page 25 of 120
4-5
4
WARNING
Improper adjustment of the speed limiter and
throttle could cause throttle cable damage or
improper throttle operation. You could lose
control, have an accident or be injured. Do not
turn the adjusting screw out more than 5 mm
(0.2 in).Engine speed limiter plate
TIPStore the speed limiter plate with the owner’s manual
so that it is readily available whenever you want to
reduce the top engine speed.
With this plate installed, the engine speed is limited
to 4800 r/min. With this plate removed, top engine
speed (8000 r/min) is available.
Remove the plate as follows.
1. Remove the seat. (See page 4-11.)
3. Pull the plate out of its case. 4. Tighten the screw.
2. Loosen the screws.
5. Install the seat.
1. Speed limiter plate
2. Screws
21