engine YAMAHA YFZ450R 2018 User Guide

4-3
4
If the warning light does not come on initially when
the key is turned to “ ” (on), or if the warning
light remains on, have a Yamaha dealer check the
electrical circuit.
EBU18067Handlebar switchesEBU18081Engine stop switch “ / ”
Set this switch to “ ” before starting the engine.
The engine stop switch controls the ignition and
stops the engine when it is running. Use this switch to stop the engine in an emergency situa-
tion. The engine will not start or run when this
switch is set to “ ”.
EBU18102Start switch “ ”
Push this switch to crank the engine with the start-
er. See the starting instructions on page 6-1 prior
to starting the engine.EBU18157Light switch “ / /OFF”
Set this switch to “ ” to turn on the low beams
and the taillight. Set the switch to “ ” to turn on
the high beams and the taillight. Set the switch to
“OFF” to turn off all the lights.NOTICEECB00046Do not use the headlights with the engine
turned off for an extended period of time. The
battery may discharge to the point that the
starter will not have enough power to crank the
engine. If this should happen, remove the bat-
tery and recharge it. (See page 8-42.)
1. Light switch “ / /OFF”
2. Engine stop switch “ / ”
3. Start switch “ ”
1
23
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EBU18284Throttle leverPush the throttle lever to increase engine speed
and the speed of the ATV. Because the throttle is
spring-loaded, the ATV will decelerate and the en-
gine will return to an idle any time the throttle lever
is released.TIPBefore 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.
EBU18325Speed limiterThe speed limiter keeps the throttle from fully
opening, even when the throttle lever is pushed to
the maximum.
Adjusting the speed limiter1. Loosen the locknut.
2. To increase the maximum engine poweravailable and the maximum speed of the ATV,
turn the adjusting screw in direction (a). To
decrease the maximum engine power avail-
able and the maximum speed of the ATV, turn
1. Throttle lever
1
1. Locknut
2. Adjusting screw
3. No more than 12 mm (0.47 in)
3
12
(a)
(b)
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4-6
4The brake lever is located on the right handlebar.
To apply the front brake, pull the brake lever to-
ward the handlebar grip.
The brake lever is equipped with a position adjust-
ing bolt. To adjust the distance between the brake
lever and the handlebar grip, hold the brake lever
away from the handlebar so it does not contact
the adjusting bolt, loosen the locknut, turn the ad-
justing bolt, and then tighten the locknut.
EBU18434Brake pedal
The brake pedal is located on the right side of the
ATV. To apply the rear brake, push down on the
brake pedal.EBU18521Parking brake leverUse the parking brake before starting the engine
or parking the ATV, especially on a slope. To apply
the parking brake, move the parking brake lever in
direction (a). To release the parking brake, move
the parking brake lever in direction (b).
1. Brake pedal
1
1. Parking brake lever (locked position)
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WARNING
EWB00221Always set the parking brake before starting
the engine. The ATV could start moving un-
expectedly if the parking brake is not ap-
plied. This could cause loss of control or a
collision.
 Always be sure you have released the park-
ing brake before you begin to ride. The brake
could overheat if you ride the ATV without re-
leasing the parking brake. You could lose braking performance which could cause an
accident. You could also wear out the brakes
prematurely.
EBU18532Shift pedalThe shift pedal is located on the left side of the en-
gine and is used in combination with the clutch
when shifting. (See page 6-2.)
1. Parking brake lever (unlocked position)
1. Shift pedal
1
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EBU18722Fuel tank capRemove the fuel tank cap by turning it counter-
clockwise.EBU37251FuelMake sure there is sufficient gasoline in the tank
before starting off. This model has been designed
to use premium unleaded gasoline of RON 97. If
knocking or pinging occurs, use a gasoline of a
higher octane (research octane number) or a dif-
ferent brand. Use of unleaded fuel will extend
spark plug life and reduce maintenance costs.
WARNING
EWB02522Gasoline and gasoline vapors are extremely
flammable. To avoid fires and explosions and
to reduce the risk of injury when refueling, fol-
low these instructions. 1. Before refueling, turn off the engine and besure that no one is sitting on the vehicle. Nev-
er refuel while smoking, or while in the vicinity
of sparks, open flames, or other sources of
ignition such as the pilot lights of water heat-
ers and clothes dryers.
2. When refueling, be sure to select the recom- mended fuel as specified. Do not overfill the
fuel tank. Since fuel expands when heated,
stop filling when the fuel reaches the bottom
of the filler tube. Otherwise heat from the en-
gine or sun can cause the fuel to expand and
spill out of the fuel tank.
1. Fuel tank cap
1
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TIPWhen refueling, check that the gasoline pump
nozzle has the same identification mark. NOTICEECB00071Use only unleaded gasoline. The use of leaded
gasoline will cause severe damage to internal
engine parts, such as the valves and piston
rings, as well as to the exhaust system.
1. Maximum fuel level
2. Fuel tank filler tubeRecommended fuel:Premium unleaded gasoline, octane 97 or
higher
Fuel tank capacity: 10.0 L (2.64 US gal, 2.20 Imp.gal)
Fuel reserve amount: 3.4 L (0.90 US gal, 0.75 Imp.gal)
2
1
1. EN228 fuel identification mark
E10
1
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EBU19203
PRE-OPERATION CHECKS
EBU19226Inspect your vehicle each time you use it to make sure the vehicle is in safe operating condition. Always
follow the inspection and maintenance procedures and schedules described in the Owner’s Manual.
WARNING
EWB00482Failure to inspect or maintain the vehicle properly increases the possibility of an accident or equip-
ment damage. Do not operate the vehicle if you find any problem. If a problem cannot be corrected
by the procedures provided in this manual, have the vehicle inspected by a Yamaha dealer. Before using this vehicle, check the following points:
ITEMROUTINE PAGE
Fuel • Check fuel level in fuel tank,
and add recommended fuel if neces-
sary.
• Check fuel line for leakage. Correct if necessary. 4-8, 5-4
Engine oil • Check oil level in engine oil tank, and add recommended oil to
specified level if necessary.
• Check ATV for oil leakage. Correct if necessary. 5-4, 8-14
Coolant • Check coolant level in reservoir, and add recommended coolant to
specified level if necessary.
• Check cooling system for leakage. Correct if necessary. 5-4, 8-20
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EBU19542FuelMake sure that there is sufficient fuel in the tank.
(See page 4-8.)EBU19561Engine oilMake sure that the engine oil is at the specified
level. Add oil as necessary. (See page 8-14.)EBU19632CoolantMake sure that the coolant is at the specified level.
Add coolant as necessary. (See page 8-20.)TIPThe coolant level must be checked on a cold en-
gine since the level varies with engine tempera-
ture. EBU19713Front and rear brakesBrake lever and brake pedal
Check that there is no free play in the brake le-
ver. If there is free play, have a Yamaha dealer
check the brake system. 
Check for correct brake pedal height. (See page
8-32.) If the pedal height is incorrect, have a
Yamaha dealer adjust it.
 Check the operation of the lever and pedal.
They should move smoothly and there should
be a firm feeling when the brakes are applied. If
not, have a Yamaha dealer check the brake sys-
tem.
Brake fluid level
Check the brake fluid level. Add fluid if necessary.
(See page 8-29.)
Brake fluid leakage
Check to see if any brake fluid is leaking out of the
pipe joints or brake fluid reservoirs. Apply the
brakes firmly for one minute. If there is any leak-
age, have a Yamaha dealer check the brake sys-
tem. Specified brake fluid:
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EBU19882
OPERATION
EBU19902Read the Owner’s Manual carefully before riding
the ATV. If there is a control or function you do not
understand, ask your Yamaha dealer.
WARNING
EWB00632Read the Owner’s Manual carefully to become
familiar with all controls in order to help pre-
vent any loss of control, which could cause an
accident or injury. EBU29954Starting the engineNOTICEECB00151See the “Engine break-in” section on page 6-4
prior to operating the engine for the first time. 1. Set the parking brake.
2. Turn the key to “ ” (on) and the engine stopswitch to “ ”.
The following warning lights should come on
for a few seconds, then go off. 
Coolant temperature warning light
 Fuel level warning light
 Engine trouble warning light
NOTICEECB00826To avoid possible damage, do not operate the
ATV if a warning light does not work as de-
scribed above. 3. Shift the transmission into neutral. The neutral
indicator light should come on, if it does not
come on, have a Yamaha dealer check the
electrical circuit.TIPThis model is equipped with an ignition circuit cut-
off system. The engine can be started under the
following conditions.
The transmission is in neutral.
 The clutch is disengaged with the transmission
in gear. However, it is recommended to shift
into neutral before starting the engine. 4. Completely close the throttle lever and start
the engine by pushing the start switch.
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6
TIPIf the engine fails to start, release the start switch,
then push it again. Pause a few seconds before
the next attempt. Each cranking should be as
short as possible to preserve battery energy. Do
not crank the engine more than 10 seconds on
each attempt. NOTICEECB00164For maximum engine life, never accelerate
hard when the engine is cold! EBU20525ShiftingThis ATV has a 5-speed forward transmission. The
transmission allows you to control the amount of
power you have available at a given speed or for
starting, accelerating, climbing hills, etc.
To shift into neutral, release the throttle lever, ap-
ply the clutch, and then repeatedly depress the
shift pedal until it stops.
When it stops, it will be in first gear. Raise the ped-
al slightly to reach the neutral position, and then
release the clutch.
EBU20595To start out and accelerate1. Release the throttle lever, apply the front or rear brake, and then release the parking
brake.
2. Pull the clutch lever to disengage the clutch.
3. Shift into first gear, and then release the brake. NOTICE: Always close the throttle
before shifting gears, otherwise damage
to the engine and drive train may result.
[ECB01220]
1. Shift pedal
2. Neutral position
1
1
N
2 3
4
5
2
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