2018 YAMAHA YFZ450R check engine

8-23
8
8. Wash the sponge material gently but thor-
oughly in solvent. WARNING! Always use
parts cleaning solvent. Never use low-
flash-point solvents or gasoline because
the engine could catch fire or explode.
[EWB01943]
9. Squeeze the excess solvent out of the sponge material and let it dry. NOTICE: Do
not twist the sponge material when
squeezing it.
[ECB00442]
10. Check the sponge material and replace it if damaged.
11. Apply Yamaha foam air filter oil or other qual- ity foam air filter oil to the sponge material.TIPThe sponge material should be wet but not drip-
ping. 12. Pull the sponge material over the air filter ele-ment frame.
13. Apply all-purpose grease to the air filter ele- ment seat.
1. Sponge material
2. Air filter element frame
1
2
UBW261E0.book Page 23 Friday, May 26, 2017 9:38 AM

8-25
8
17. Install the seat.
TIPThe air filter element should be cleaned every 20–
40 hours. It should be cleaned and lubricated
more often if the ATV is operated in extremely
dusty areas. Each time the air filter element main-
tenance is performed, check the air inlet of the air
filter case for obstructions. Check the air filter
case rubber joint to the throttle body and the rub-
ber joint manifold fittings for an air-tight seal.
Tighten all fittings securely to avoid the possibility
of unfiltered air entering the engine. EBU30862Cleaning the spark arresterSelect a well-ventilated area free of combustible
materials and make sure the exhaust and muffler
are cool.
1. Remove the tailpipe cover by removing the bolts. 2. Remove the retainer by removing the bolts,
and then remove the tailpipe and gasket from
the muffler.
1. Tailpipe cover
2. Bolt2
1 2
UBW261E0.book Page 25 Friday, May 26, 2017 9:38 AM

8-27
8
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.
EBU29704Adjusting the throttle lever free playPeriodically check the throttle lever free play and
adjust if necessary.1. Slide the rubber cover back.
2. Loosen the locknut.
Tightening torque:
Tailpipe cover bolt:8 N·m (0.8 kgf·m, 5.9 lb·ft)1. Rubber cover
2. Throttle lever free play adjusting bolt
3. Locknut
4. Throttle lever free playThrottle lever free play: 2.0–4.0 mm (0.08–0.16 in)
32
4
(a)(b)
1
UBW261E0.book Page 27 Friday, May 26, 2017 9:38 AM

8-28
83. 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.
EBU24061Valve 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 and lu-
brication 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.
EBU24131Checking the front and rear brake padsThe front and rear brake pads must be checked
for wear at the intervals specified in the periodic
maintenance and lubrication chart.EBU29561Front brake pads
Each brake pad is provided with wear indicator
grooves, which allow you to check the brake pad
wear without having to disassemble the brake. To
check the brake pad wear, check the wear indica-
tor grooves. If a brake pad has worn to the point
that the wear indicator grooves have almost dis-
appeared, have a Yamaha dealer replace the
brake pads as a set.
UBW261E0.book Page 28 Friday, May 26, 2017 9:38 AM

8-38
82. Wipe the drive chain dry.
3. Thoroughly lubricate the drive chain with a
special O-ring chain lubricant. NOTICE: Do
not use engine oil or any other lubricants
for the drive chain, as they may contain
substances that could damage the O-
rings.
[ECB00582]
EBU24905
Checking 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
EWB02582
Inspect 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.
1. O-rings
1
1
Recommended lubricant:
Yamaha cable lubricant or other suitable cable lubricant
UBW261E0.book Page 38 Friday, May 26, 2017 9:38 AM

8-51
8
EBU27695Troubleshooting 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.
UBW261E0.book Page 51 Friday, May 26, 2017 9:38 AM

8-52
8Engine 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. TIPIf coolant is not available, tap water can be temporarily used instead, provided that it is changed to the
recommended coolant as soon as possible. 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.
UBW261E0.book Page 52 Friday, May 26, 2017 9:38 AM

12-1
12
INDEX
AAccessories and loading ................................................ 6-5
Air filter element, cleaning ........................................... 8-21BBattery ......................................................................... 8-42
Brake and clutch levers, checking and lubricating ...... 8-39
Brake fluid, changing ................................................... 8-31
Brake fluid level, checking ........................................... 8-29
Brake lever ..................................................................... 4-5
Brake lever free play, checking the front ..................... 8-31
Brake light switches ..................................................... 8-34
Brake pads, checking the front and rear ..................... 8-28
Brake pedal .................................................................... 4-6
Brake pedal, checking and lubricating ........................ 8-39
Brake pedal height, checking ...................................... 8-32
Brakes .......................................................................... 8-28
Brakes, front and rear .................................................... 5-4CCables, checking and lubricating ................................ 8-38
Chassis fasteners .......................................................... 5-7
Cleaning ......................................................................... 9-1
Clutch lever .................................................................... 4-5
Clutch lever free play, adjusting .................................. 8-34
Coolant .................................................................5-4, 8-20
Coolant temperature warning light ................................ 4-2
Cowling and panels, removing and installing .............. 8-10DDrive chain ..................................................................... 5-5
Drive chain, lubricating ................................................ 8-37 Drive chain slack .......................................................... 8-35
EEngine break-in .............................................................. 6-4
Engine oil ....................................................................... 5-4
Engine oil and oil filter element .................................... 8-14
Engine, start ................................................................... 6-1
Engine stop switch ........................................................ 4-3
Engine trouble warning light .......................................... 4-2FFuel ......................................................................... 4-8, 5-4
Fuel level warning light .................................................. 4-2
Fuel tank cap ................................................................. 4-8
Fuse, replacing ............................................................ 8-45HHandlebar position, adjusting ...................................... 4-23
Handlebar switches ....................................................... 4-3
Headlight beam, adjusting ........................................... 8-48
Headlight bulb, replacing ............................................. 8-46IIdentification numbers ................................................. 11-1
Indicator light and warning lights ................................... 4-1
Instruments, lights and switches ................................... 5-7LLabel locations ............................................................... 1-1
Light switch ................................................................... 4-3MMain switch .................................................................... 4-1
Maintenance and lubrication chart ................................ 8-5
Maintenance chart, emission control system ................ 8-3
UBW261E0.book Page 1 Friday, May 26, 2017 9:38 AM