2021 YAMAHA YFZ50 tires

EBU17421
TABLE OF CONTENTS
VEHICLE IDENTIFICATION ............................ 1-1Identification numbers ................................ 1-1
LOCATION OF THE WARNING AND
SPECIFICATION LABELS .............................. 2-1
SAFETY INFORMATION ................................ 3-1
DESCRIPTION................................................ 4-1 Left view ...................................................... 4-1
Right view.................................................... 4-1
Controls and instruments............................ 4-2
INSTRUMENT AND CONTROL
FUNCTIONS ................................................... 5-1 Main switch ................................................. 5-1
Handlebar switches .................................... 5-1
Engine stop switch with lanyard ................. 5-2
Throttle lever ............................................... 5-3
Speed limiter ............................................... 5-3
Front brake lever ......................................... 5-5
Rear brake lever .......................................... 5-6
Parking brake .............................................. 5-6
Kickstarter ................................................... 5-7 Fuel tank cap .............................................. 5-8
Fuel ............................................................. 5-9
Fuel cock .................................................. 5-10
Starter (choke) ......................................... 5-12
Seat .......................................................... 5-13
Rear shock absorber ................................ 5-13
PRE-OPERATION CHECKS .......................... 6-1 Fuel ............................................................. 6-3
Engine oil .................................................... 6-3
Transmission oil .......................................... 6-3
Front and rear brakes ................................. 6-3
Throttle lever ............................................... 6-3
Drive chain .................................................. 6-3
Tires ............................................................ 6-3
Chassis fasteners ....................................... 6-6
Instruments and switches........................... 6-6
OPERATION .................................................. 7-1 Starting a cold engine................................. 7-1
Starting a warm engine............................... 7-3
Engine break-in........................................... 7-3
Parking........................................................ 7-3
Parking on a slope ...................................... 7-4UBW464E0.book Page 1 Thursday, January 23, 2020 2:42 PM

2-6
2
E10E5
**.* kPa
*.** kgf/cm²
*.* psi **.* kPa
*.** kgf/cm²
*.* psi
This unit contains high-pressure nitrogen
gas.
Mishandling can cause an explosion. Do not
incinerate, puncture or open.
EN228 fuel identification mark.
Gasoline of ethanol 10% or less can be
used. EN228 fuel identification mark.
Gasoline of ethanol 5% or less can be used.
Use unleaded gasoline only. Measure the tire pressure when the tires are
cold.
Adjust the tire pressure.
Improper tire pressure can cause loss of
control.
Loss of control can result in severe injury or
death.
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3-3
3surfaces. Shift your weight to the uphill side of
the ATV. Never attempt to turn the ATV around
on any hill until you have mastered the turning
technique described in this manual on level
ground. Avoid crossing the side of a steep hill if
possible.
 Always use proper procedures if you stall or roll
backwards 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
reduce the chance of skidding or sliding out of
control. 
Never operate an ATV in fast flowing water or in
water deeper than that recommended in this
manual. Remember that wet brakes may have
reduced 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 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.
 Do not operate your ATV during darkness un-
less it is equipped with a properly functioning
headlight. Off-road riding is inherently danger-
ous and additionally, off-road trails do not have
streetlights to guide you.
 Never maintain an ATV without proper knowl-
edge. Contact an authorized ATV dealer to in-
form you on basic ATV maintenance. Certain
maintenance can only be carried out by certified
staff.
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6-2
6
Throttle lever• Make sure that operation is smooth. Lubricate cable and lever
housing if necessary.
• Check lever free play, and adjust if necessary. 6-3, 9-22
Control cables • Make sure that operation is smooth. Lubricate if necessary. 9-29
Drive chain • Check chain slack, and adjust if necessary.
• Check chain condition. Lubricate if necessary. 6-3, 9-26, 9-29
Wheels and tires • Check wheel condition, and replace if damaged.
• Check tire condition and tread depth. Replace if necessary.
• Check air pressure. Correct if necessary. 6-3
Brake levers • Make sure that operation is smooth. Lubricate lever pivoting points
if necessary. 9-30
Chassis fasteners • Make sure that all nuts, bolts and screws are properly tightened. 6-6
Instruments and switches • Check operation, and correct if necessary. 6-6
ITEM ROUTINE PAGE
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6-3
6
EBU38000FuelMake sure there is sufficient gasoline in the tank
before starting off. Refuel if necessary. (See page
5-9.)EBU19561Engine oilMake sure that the engine oil is at the specified
level. Add oil as necessary. (See page 9-11.)EBU34490Transmission oilMake sure that the transmission oil is at the spec-
ified level. Add oil as necessary. (See page 9-15.)EBU19653Front and rear brakesBrake levers
Check for correct free play in the brake levers. If
the free play is incorrect, adjust it. (See pages
9-24 and 9-26.)
 Check operation of the levers. They should
move smoothly and there should be a firm feel-
ing when the brake is applied. If not, have the
ATV checked by a Yamaha dealer. Brake operation
Test the brakes at slow speed after starting out to
make sure they are working properly. If the brakes
do not provide proper braking performance,
check the brake shoes for wear. (See page 9-23.)
EBU19762Throttle leverCheck the operation of the throttle lever. It must
open smoothly and spring back to the idle position
when released. Have a Yamaha dealer correct if
necessary.EBU19771Drive chainCheck the condition of the drive chain and check
the drive chain slack. Lubricate and adjust the
drive chain as necessary. (See page 9-26.)EBU1979ATiresCheck tire pressure regularly to make sure it is at
the recommended specifications. Also check for
wear and damage.
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6-4
6
Tire pressure
Use a tire pressure gauge to check and adjust tire
air pressure when the tires are cold. The tire air
pressure must be equal on both sides.
WARNING! Operation of this vehicle with im- proper tire pressure may cause severe injury or
death from loss of control or rollover. Tire
pressure below the minimum specified could
also cause the tire to dislodge from the rim un-
der severe riding conditions.
[EWB02542]
Tire pressure gauge
A low-pressure tire gauge is included as standard
equipment with your vehicle. (See page 9-2.)
When using the tire pressure gauge, make two
measurements and use the second reading as grit
in the gauge or tire valve could have caused the
first reading to be incorrect.
Tire wear
If the tire is damaged or the tire tread depth de-
creases to 3 mm (0.12 in) or less, replace the tire.
Recommended tire pressure:
Front15.0 kPa (0.150 kgf/cm², 2.2 psi)
Rear 15.0 kPa (0.150 kgf/cm², 2.2 psi)
Minimum tire pressure: Front12.0 kPa (0.120 kgf/cm², 1.7 psi)
Rear 12.0 kPa (0.120 kgf/cm², 1.7 psi)
Maximum tire seating pressure: Front250 kPa (2.5 kgf/cm², 36 psi)
Rear 250 kPa (2.5 kgf/cm², 36 psi)1. Low-pressure tire gauge
2. Tire air valve
1
2
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6-5
6Tire information
This ATV is equipped with tubeless tires and tire
air valves. After extensive tests, only the tires list-
ed below are approved for this model by Yamaha. Aftermarket tires and rims
The tires and rims that came with your ATV were
designed to match the performance capabilities
and to provide the best combination of handling,
braking, and comfort. Other tires, rims, sizes, and
combinations may not be appropriate.
WARNING
EWB02552Use of improper tires on this ATV may cause
loss of control, increasing your risk of an acci-
dent.
1. Tire tread depth
Front:
Manufacturer/model:DURO/DI2040
Size: AT 1 6 x 6 . 5 - 7
Rear: Manufacturer/model:DURO/DI2041
Size: AT 1 6 x 7 - 7
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8
abruptly, the vehicle may lurch forward or the front
wheels may lift off the ground, resulting in a loss of
directional control. Avoid higher speeds until you
are thoroughly familiar with the operation of your
ATV.
When slowing down or stopping, release the
throttle and apply the brakes smoothly and evenly.
Improper use of the brakes can cause the tires to
lose traction, reducing control and increasing the
possibility of an accident.
TURNING YOUR ATV
WARNING
EWB01772Always follow proper procedures for turning as
described in this Owner’s Manual. Practice
turning at low speeds before attempting to turn
at faster speeds. Do not turn at speeds too fast
for your skills or the conditions. ATV could go
out of control, causing a collision or overturn. To achieve maximum traction on unpaved surfac-
es, the two rear wheels turn together at the same
speed. Therefore, unless the wheel on the inside
of the turn is allowed to slip or lose some traction,
the ATV will resist turning. A special turning tech- nique must be used to allow the ATV to make
turns quickly and easily. It is essential that this skill
be learned first at low speed.
As you approach a curve, slow down and begin to
turn the handlebars in the desired direction. As
you do so, put your weight on the footboard to the
outside of the turn (opposite your desired direc-
tion) and lean your upper body into the turn. Use
the throttle to maintain an even speed through the
turn. This maneuver will let the wheel on the inside
of the turn slip slightly, allowing the ATV to make
the turn properly.UBW464E0.book Page 12 Thursday, January 23, 2020 2:42 PM