2018 YAMAHA YFZ450R Throttle

EBU17421
TABLE OF CONTENTS
LOCATION OF THE WARNING AND
SPECIFICATION LABELS .............................. 1-1
SAFETY INFORMATION ................................ 2-1
DESCRIPTION................................................ 3-1Left view ...................................................... 3-1
Right view.................................................... 3-1
Controls and instruments............................ 3-2
INSTRUMENT AND CONTROL
FUNCTIONS ................................................... 4-1 Main switch ................................................. 4-1
Indicator light and warning lights ................ 4-1
Handlebar switches .................................... 4-3
Throttle lever ............................................... 4-4
Speed limiter ............................................... 4-4
Clutch lever ................................................. 4-5
Brake lever .................................................. 4-5
Brake pedal ................................................. 4-6
Parking brake lever ..................................... 4-6
Shift pedal ................................................... 4-7
Fuel tank cap............................................... 4-8
Fuel ............................................................. 4-8 Seat .......................................................... 4-10
Front shock absorbers ............................. 4-11
Rear shock absorbers .............................. 4-16
Handlebar position ................................... 4-23
PRE-OPERATION CHECKS .......................... 5-1 Fuel ............................................................. 5-4
Engine oil .................................................... 5-4
Coolant ....................................................... 5-4
Front and rear brakes ................................. 5-4
Throttle lever ............................................... 5-5
Drive chain .................................................. 5-5
Tires ............................................................ 5-5
Chassis fasteners ....................................... 5-7
Instruments, lights and switches ................ 5-7
OPERATION .................................................. 6-1 Starting the engine ..................................... 6-1
Shifting........................................................ 6-2
Engine break-in........................................... 6-4
Parking........................................................ 6-4
Parking on a slope ...................................... 6-5
Accessories and loading ............................ 6-5UBW261E0.book Page 1 Friday, May 26, 2017 9:38 AM

RIDING YOUR ATV ........................................ 7-1GETTING TO KNOW YOUR ATV ................ 7-2
RIDE WITH CARE AND GOOD JUDGMENT .............................................. 7-2
BE CAREFUL WHERE YOU RIDE ............... 7-8
TURNING YOUR ATV................................ 7-11
CLIMBING UPHILL ................................... 7-13
RIDING DOWNHILL .................................. 7-16
CROSSING A SLOPE................................ 7-17
CROSSING THROUGH SHALLOW WATER .................................................... 7-18
RIDING OVER ROUGH TERRAIN ............. 7-20
SLIDING AND SKIDDING.......................... 7-20
WHAT TO DO IF... ..................................... 7-21
WHAT TO DO... ......................................... 7-22
PERIODIC MAINTENANCE AND
ADJUSTMENT................................................ 8-1 Owner’s manual and tool kit ....................... 8-2
Periodic maintenance chart: Emission control system .......................................... 8-3
Periodic maintenance chart: General maintenance and lubrication..................... 8-5
Removing and installing the cowling and panels...................................................... 8-10
Checking the spark plug ........................... 8-13
Engine oil and oil filter element ................. 8-14 Coolant ..................................................... 8-20
Cleaning the air filter element ................... 8-21
Cleaning the spark arrester ...................... 8-25
Adjusting the throttle lever free play ......... 8-27
Valve clearance......................................... 8-28
Brakes....................................................... 8-28
Checking the front and rear brake pads... 8-28
Checking the brake fluid level .................. 8-29
Changing the brake fluid .......................... 8-31
Checking the front brake lever free play... 8-31
Checking the brake pedal height.............. 8-32
Adjusting the parking brake free play ....... 8-32
Brake light switches ................................. 8-34
Adjusting the clutch lever free play .......... 8-34
Drive chain slack....................................... 8-35
Lubricating the drive chain ....................... 8-37
Checking and lubricating the cables ........ 8-38
Checking and lubricating the brake and
clutch levers ........................................... 8-39
Checking the shift pedal ........................... 8-39
Checking and lubricating the brake pedal ....................................................... 8-39
Checking the wheel hub bearings ............ 8-40
Lubricating the swingarm pivots .............. 8-40
Lubricating the upper and lower arm pivots ...................................................... 8-41
Lubricating the steering shaft ................... 8-42UBW261E0.book Page 2 Friday, May 26, 2017 9:38 AM

2-2
2
Never operate at speeds too fast for your skills
or the riding conditions. Always go at a speed
that is proper for the terrain, visibility, operating
conditions, and your experience.
 Never attempt wheelies, jumps, or other stunts.
 Always inspect your ATV each time you use it to
make sure it is in safe operating condition. Al-
ways follow the inspection and maintenance
procedures and schedules described in this
manual.
 Always keep both hands on the handlebars and
both feet on the footrests of the ATV during op-
eration.
 Always go slowly and be extra careful when op-
erating on unfamiliar terrain. Always be alert to
changing terrain conditions when operating the
ATV.
 Never operate on excessively rough, slippery or
loose terrain until you have learned and prac-
ticed the skills necessary to control the ATV on
such terrain. Always be especially cautious on
these kinds of terrain.
 Always follow proper procedures for turning as
described in this manual. Practice turning at low
speeds before attempting to turn at faster
speeds and never turn at excessive speeds. 
Never operate the ATV on hills too steep for the
ATV or for your abilities. Practice on smaller hills
before attempting larger hills.
 Always follow proper procedures for climbing
hills as described in this manual. Check the ter-
rain carefully before you start up any hill. Never
climb hills with excessively slippery or loose
surfaces. Shift your weight forward. Never open
the throttle suddenly or make sudden gear
changes. Never go over the top of a hill at high
speed.
 Always follow proper procedures for going
down hills and for braking on hills as described
in this manual. Check the terrain carefully before
you start down any hill. Shift your weight back-
ward. Never go down a hill at high speed. Avoid
going down a hill at an angle that would cause
the vehicle to lean sharply to one side. Go
straight down the hill where possible.
 Always follow proper procedures for crossing
the side of a hill as described in this manual.
Avoid hills with excessively slippery or loose
surfaces. 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
UBW261E0.book Page 2 Friday, May 26, 2017 9:38 AM

3-2
3
EBU17715Controls and instruments1. Clutch lever
2. Parking brake lever
3. Handlebar switches
4. Main switch
5. Front brake fluid reservoir
6. Throttle lever
7. Brake lever
2
1
3
6
5
4
7
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4-4
4
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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4-5
4
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 8-27.)
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 6-1.)EBU18425Brake 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
23
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4-19
4
7. Loosen the clamp screw at the throttle body
side, and then disconnect the air intake duct
from the throttle body.
8. Loosen the locknut.
9. Turn the spring preload adjusting nut in direc- tion (a) to increase the spring preload and
thereby harden the suspension, and in direc-
tion (b) to decrease the spring preload and
thereby soften the suspension.
TIPA special wrench can be obtained at a Yamaha
dealer to make this adjustment.
 The spring preload setting is determined by
measuring distance A, shown in the illustration.
The shorter distance A is, the higher the spring
preload; the longer distance A is, the lower the
spring preload. With each complete turn of the
adjusting nut, distance A is changed by 1.5 mm
(0.06 in).
1. Clamp screw
2. Air intake duct
1
2
1. Locknut
2. Spring preload adjusting nut
3. Special wrench
213
(a)
(b)
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4-20
410. Tighten the locknut to the specified torque. NOTICE: Always tighten the locknut
against the adjusting nut, and then tighten
it to the specified torque.
[ECB00082]
11. Connect the air intake duct to the throttle body, and then tighten the clamp screw at the
throttle body side. NOTICE: Make sure that
the air intake duct is properly connected to
the throttle body, and that the clamp
screw is tightened securely.
[ECB00962]
12. Connect the coupler.
13. Connect the air filter case to the air intake duct, place the air filter case in the original po-
sition, and then tighten the clamp screw at
the air filter case side. NOTICE: Make sure
that the air intake duct is properly con-
nected to the air filter case, and that the
clamp screw is tightened securely.
[ECB00972]
14. Install the air filter case bolts, and then tighten them to the specified torque.
Spring preload setting:
Minimum (soft):Distance A = 286.5 mm (11.28 in)
Standard: Distance A = 278.0 mm (10.94 in)
Maximum (hard): Distance A = 266.5 mm (10.49 in)
1. Distance A
1
Tightening torque:Locknut:30 N·m (3.0 kgf·m, 22 lb·ft)
Tightening torque: Air filter case bolt:7 N·m (0.7 kgf·m, 5.2 lb·ft)
UBW261E0.book Page 20 Friday, May 26, 2017 9:38 AM