2021 YAMAHA YFZ450R ignition

5-3
5
The electrical circuit of the warning light can be
checked by turning the key to “ ” (on). The
warning light should come on for a few seconds,
and then go off.
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.
EBU18068Handlebar switches
EBU18081Engine 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 7-1 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
1. Light switch “ / /OFF”
2. Engine stop switch “ / ”
3. Start switch “ ”
1
23
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5-5
5
the adjusting screw in direction (b). Do not
turn the adjusting screw out more than 12
mm (0.47 in) or the throttle cable could be
damaged. Always make sure the throttle lever
free play is adjusted to 2.0–4.0 mm (0.08–
0.16 in). (See page 9-28.)
WARNING! Im-
proper adjustment of the speed limiter and
throttle could cause throttle cable damage
or improper throttle operation. You could
lose control, resulting in an accident.
[EWB00242]
3. Tighten the locknut.EBU18384Clutch lever
The clutch lever is located on the left side of the
handlebar. To disengage the clutch, pull the clutch
lever toward the handlebar grip. To engage the
clutch, release the lever. The lever should be
pulled rapidly and released slowly for smooth
clutch operation.
The clutch lever is equipped with a clutch switch,
which is part of the ignition circuit cut-off system.
(See page 7-1.)EBU18426Brake lever
1. Clutch lever
1. Brake lever
2. Locknut
3. Brake lever position adjusting bolt
4. Distance between brake lever and handlebar grip
1
4
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5-8
5
EBU37980Fuel tank capRemove the fuel tank cap by turning it counter-
clockwise.
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. Do not overfill the fuel tank. When refueling, be sure to insert the pump nozzle into the fuel
tank filler hole. Stop filling when the fuel
reaches the bottom of the filler tube. Because
fuel expands when it heats up, heat from the
engine or the sun can cause fuel to spill out of
the fuel tank.1. Fuel tank cap
1
1. Maximum fuel level
2. Fuel tank filler tube
2
1
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7-1
7
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 7-4
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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9-43
9
TIPFor parts equipped with a grease nipple, use a
grease gun. EBU2918BBatteryThis model is equipped with a 12-volt VRLA
(valve-regulated lead-acid) battery. There is no
need to check the electrolyte or to add distilled
water. However, the battery lead connections
need to be checked and tightened, and the bat-
tery terminals cleaned if corroded. If the battery
seems to have discharged, recharge it as soon as
possible.TIPWear gloves and eye protection in a ventilated
area away from sparks and open flames. Wash
hands after handling.
 It is recommended to have the battery serviced
by a Yamaha dealer.
WARNING
EWB02161Battery electrolyte is poisonous and danger-
ous, as it contains sulfuric acid, which can
cause severe burns. Avoid contact with skin,
eyes or clothing. Always shield your eyes when
working near batteries.
Antidote:
EXTERNAL: Flush with water.
INTERNAL: Drink large quantities of water or
milk. Follow with milk of magnesia, beaten egg
or vegetable oil. Call a physician immediately.
EYES: Flush with water for 15 minutes and get
prompt medical attention.
Batteries produce explosive gases. Keep
sparks, flame, cigarettes or other sources of
ignition away. Ventilate when charging or using
in an enclosed space.
KEEP OUT OF REACH OF CHILDREN. To remove the battery
1. Remove the seat. (See page 5-10.)
2. Remove the battery holding plate by remov- ing the bolts.
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9-50
9
EBU27484Installing a wheel1. Install the wheel with the arrow mark pointingin the forward rotating direction of the wheel,
and then install the wheel nuts.
2. Lower the ATV to the ground.
3. Tighten the wheel nuts to the specified torques.
EBU25741TroubleshootingAlthough Yamaha ATVs receive a thorough in-
spection before shipment from the factory, trouble
may occur during operation. Any problem in the
fuel, compression, or ignition systems, for exam-
ple, can cause poor starting and loss of power.
The following troubleshooting charts represent
quick and easy procedures for checking these vi-
tal systems yourself. However, should your ATV
require any repair, take it to a Yamaha dealer,
whose skilled technicians have the necessary
tools, experience, and know-how to service the
ATV properly.
Use only genuine Yamaha replacement parts. Im-
itation parts may look like Yamaha parts, but they
are often inferior, have a shorter service life and
can lead to expensive repair bills.
1. Arrow mark
2. Forward rotating direction
3. Wheel nut
2
3
3
Tightening torques: Front wheel nut:45 N·m (4.5 kgf·m, 33 lb·ft)
Rear wheel nut: 45 N·m (4.5 kgf·m, 33 lb·ft)
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9
EBU27696Troubleshooting chartsStarting problems or poor engine performance
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.There is no fuel.
Check the battery.
Supply fuel.
The engine does not start.
Check the battery.
Operate the electric starter.4. Compression
There is compression.
There is no compression.
The engine does not start.
Have a Yamaha dealer check the ATV.
Remove the spark plug
and check the electrodes.3. Ignition
Wipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug. Have a Yamaha dealer check the ATV.
The engine does not start.
Check the compression.
DryWet
Operate the electric starter.
Have a Yamaha dealer check the ATV.
The engine does not start.
Check the ignition.
Operate the electric starter.2. Battery
The engine turns over
quickly.
The engine turns over
slowly.
The battery is good.Check the battery lead connections,
and have a Yamaha dealer charge
the battery if necessary.
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11-4
11
Spring:Coil spring
Shock absorber: Gas-hydraulic damper
Wheel travel:
250 mm (9.9 in)Rear suspension:Type:Swingarm (link suspension)
Spring:
Coil spring
Shock absorber: Gas-hydraulic damper
Wheel travel: 280 mm (11.0 in)Electrical system:System voltage:12 V
Ignition system: TCI
Charging system:
AC magnetoBattery:Model:YTZ7S
Voltage, capacity:
12 V, 6.0 AhLights:Headlight:T19L, 30.0 W/30.0 W Brake/tail light:
LED
Neutral indicator light: LED
Fuel level warning light:
LED
Coolant temperature warning light: LED
Engine trouble warning light: LED
Fuses:Main fuse:20.0 AEBU30403Noise and vibration levels statement (for Eu-
rope)
The figures quoted are emission levels and are not
necessarily safe working levels. Whilst there is a
correlation between the emission and exposure
levels, this cannot be used reliably to determine
whether or not further precautions are required.
Factors that influence the actual level of exposure
of work-force include the characteristics of the
work room, the other sources of noise, etc. i.e. the
number of machines and other adjacent process-
es, and the length of time for which an operator is
exposed to the noise. Also the permissible expo-
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