Page 126 of 172

9-36
912. Install the air filter case cover by hooking the
holders onto the cover. NOTICE: Make sure
that the air filter element is properly seated
in the air filter case. Never operate the en-
gine with the air filter element removed.
Doing so would allow unfiltered air to enter
the engine, causing rapid engine wear and
possible engine damage. Additionally, the
fuel injection system would be affected re-
sulting in poor engine performance and
possible overheating.
[ECB00763]
13. Install the seat.EBU28905Cleaning the spark arresterBe sure the exhaust pipe and muffler are cool be-
fore cleaning the spark arrester.
WARNING
EWB02342Always let the exhaust system cool prior to
touching exhaust components.
Do not start the engine with the spark arrester
removed. Sparks or exhaust particulate can
cause eye injury, burns, or start a fire. 1. Remove the tailpipe bolts.
2. Remove the tailpipe by pulling it out of the muffler, and then remove the gasket.1. Gasket
2. Spark arrester
3. Tailpipe
4. Tailpipe bolt
3
2
4
1
4
UBEY60E0.book Page 36 Monday, July 27, 2020 10:46 AM
Page 129 of 172

9-39
9
For differential gear lock models
Periodically check the throttle lever free play and
adjust if necessary.
1. Slide the rubber cover back.
2. Loosen the locknut. 3. To increase the throttle lever free play, turn
the throttle lever free play adjusting bolt in di-
rection (a). To decrease the throttle lever free
play, turn the adjusting bolt in direction (b).
4. Tighten the locknut.
5. Slide the rubber cover to its original position.
EBU24062Valve clearanceThe valve clearance changes with use, resulting in
improper air-fuel mixture and/or engine noise. To
prevent this from occurring, the valve clearance
must be adjusted by a Yamaha dealer at the inter-
vals specified in the periodic maintenance chart.EBU29602BrakesReplacement of brake components requires pro-
fessional knowledge. Brake service should be
performed by a Yamaha dealer.
WARNING
EWB02572Operating with improperly serviced or adjust-
ed brakes could lead to a loss in braking ability
and an accident.
1. Throttle lever free play
2. Rubber cover
3. Locknut
4. Throttle lever free play adjusting boltThrottle lever free play: 2.0–4.0 mm (0.08–0.16 in)
2WD
4WD
3
4
2
1
(b)
(a)
UBEY60E0.book Page 39 Monday, July 27, 2020 10:46 AM
Page 131 of 172

9-41
9
TIPStraighten the handlebars for an accurate reading. NOTICEECB01161Brake fluid may damage painted surfaces or
plastic parts. Always clean up spilled fluid im-
mediately.
As the brake pads wear, it is normal for the brake
fluid level to gradually go down. A low brake fluid
level may indicate worn brake pads or brake sys-
tem leakage. Therefore, be sure to check the
brake pads for wear and the brake system for
leakage. If the brake fluid level suddenly goes
down, have a Yamaha dealer check the brake sys-
tem before further riding.
WARNING
EWB02721Improper maintenance can result in loss of
braking ability. Observe these precautions:
Insufficient brake fluid may allow air to enter
the brake system, reducing braking perfor-
mance.
Clean the filler cap before removing. Use
only DOT 4 brake fluid from a sealed contain-
er.
Use only the specified brake fluid; otherwise,
the rubber seals may deteriorate, causing
leakage.
Refill with the same type of brake fluid. Add-
ing a brake fluid other than DOT 4 may result
in a harmful chemical reaction.
1. Minimum level markSpecified brake fluid:
DOT 4
1
UBEY60E0.book Page 41 Monday, July 27, 2020 10:46 AM
Page 139 of 172

9-49
9
EBU24905Checking and lubricating the cablesThe operation and the condition of all control ca-
bles should be checked before each ride, and the
cables and cable ends should be lubricated if nec-
essary. If a cable is damaged or does not move
smoothly, have a Yamaha dealer check or replace
it.
WARNING
EWB02582Inspect cables frequently and replace if
damaged. Corrosion can result when the ca-
ble sheaths become damaged, and cables
can also become frayed or kinked, which
could restrict the operation of controls and
lead to an accident or injury.
Always make sure all control cables work
smoothly before you begin riding in cold
weather. If the control cables are frozen or do not work smoothly, you could be unable
to control the ATV, which could lead to an
accident or collision.
EBU28712Checking and lubricating the front and
rear brake leversThe operation of the front and rear brake levers
should be checked before each ride, and the lever
pivots should be lubricated if necessary.
Recommended lubricant:
Yamaha cable lubricant or other suitable cable lubricantRecommended lubricants: Front brake lever:Silicone grease
Rear brake lever: Lithium-soap-based grease
UBEY60E0.book Page 49 Monday, July 27, 2020 10:46 AM
Page 144 of 172

9-54
9
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 battery1. Remove the seat. NOTICE: When removing
the battery, the main switch must be off,
and the negative lead must be disconnect-
ed before the positive lead.
[ECB01002]
2. Remove the battery holding plate by remov- ing the bolts.
3. Disconnect the negative battery lead first, then the positive battery lead by removing
their bolts.
4. Pull the battery out of its compartment.1. Battery holding plate
2. Bolt
3. Negative battery lead (black)
4. Positive battery lead (red)
2
3
4
1
2
UBEY60E0.book Page 54 Monday, July 27, 2020 10:46 AM
Page 148 of 172
9-58
92. Remove the seat. (See page 5-18.)
3. Remove the blown fuse, and then install a
new fuse of the specified amperage.
WARNING! Always use a fuse of the spec-
ified rating, and never use a substitute ob-
ject in place of the proper fuse. An
improper fuse or a substitute object can
cause damage to the electrical system,
which could lead to a fire.
[EWB02173]
4. Turn on the main switch, start the engine, andthen turn on the circuit in question.
5. If the fuse immediately blows again, have a Yamaha dealer check the vehicle.
Specified fuses:
Main fuse:40.0 A
Headlight fuse: 15.0 A
Ignition fuse: 10.0 A
Four-wheel-drive motor fuse: 10.0 A (YFM450FWBD)
3.0 A (YFM450FWB)
Signaling system fuse: 10.0 A
Radiator fan motor fuse: 20.0 A
Auxiliary DC jack fuse: 10.0 A
Fuel injection system fuse: 10.0 A
EPS fuse: 40.0 A (YFM450FWBD)
UBEY60E0.book Page 58 Monday, July 27, 2020 10:46 AM
Page 155 of 172

9-65
9
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.
WARNING
EWB02281Do not smoke when checking the fuel system.
Fuel can ignite or explode, causing severe inju-
ry or property damage. Make sure there are no
open flames or sparks in the area, including pi-
lot lights from water heaters or furnaces.
1. Tapered nutTightening torques:Front wheel nut:55 N·m (5.5 kgf·m, 41 lb·ft)
Rear wheel nut: 55 N·m (5.5 kgf·m, 41 lb·ft)1
UBEY60E0.book Page 65 Monday, July 27, 2020 10:46 AM
Page 157 of 172
9-67
9
Engine overheating
WARNING
EWB02291Wait for the engine and radiator to cool before removing the radiator cap. You could be burned by
hot fluid and steam blown out under pressure. Always put a thick rag over the cap when opening.
Allow any remaining pressure to escape before completely removing the cap. TIP
Tap water can be used in an emergency. Change to the recommended coolant as soon as possible.
The engine will tend to overheat if the radiator is caked with mud, or if the ATV is overloaded. Wait until the
engine has cooled.
Check the coolant level in the
reservoir and radiator.
The coolant level
is OK.The coolant level is low.
Check the cooling system
for leakage.
Have a Yamaha dealer check
and repair the cooling system.Add coolant. (See TIP.)
Start the engine. If the engine overheats again, have a
Yamaha dealer check and repair the cooling system.
There is
leakage.
There is
no leakage.
UBEY60E0.book Page 67 Monday, July 27, 2020 10:46 AM