2019 YAMAHA YFZ450 maintenance

EBU17171
INTRODUCTION
EBU17323Congratulations on your purchase of the Yamaha YFZ45YSXK / YFZ45YSSK. This ATV represents the re-
sult of many years of Yamaha experience in the production of fine sporting, touring, and pacesetting racing
machines. With the purchase of this Yamaha, you can now appreciate the high degree of craftsmanship
and reliability that have made Yamaha a leader in these fields.
This manual will provide you with a good basic understanding of the features and operation of this ATV.
This manual includes important safety information. It provides information about special techni-
ques and skills necessary to ride the ATV. It also includes basic maintenance and inspection proce-
dures. If you have any questions regarding the operation or maintenance of your ATV, please consult a
Yamaha dealer.
AN IMPORTANT SAFETY MESSAGE:
 Read this manual completely before operating your ATV. Make sure you understand all instructions.
 Pay close attention to the warning and notice labels on the ATV.
 This ATV should not be ridden by anyone under 16 years of age.
 This ATV is a high-performance ATV for off-road use only, for sport-type recreational and competitive
use by experienced operators.UBW262E0.book Page 1 Tuesday, April 3, 2018 10:59 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 ......... 8-28
Valve clearance......................................... 8-28
Brakes....................................................... 8-28
Checking the front and rear brake pads... 8-29
Checking the brake fluid level .................. 8-30
Changing the brake fluid .......................... 8-31
Checking the front brake lever free play... 8-32
Checking the brake pedal height.............. 8-32
Adjusting the parking brake free play ....... 8-33
Brake light switches ................................. 8-34
Adjusting the clutch lever free play .......... 8-35
Drive chain slack....................................... 8-36
Lubricating the drive chain ....................... 8-38
Checking and lubricating the cables ........ 8-38
Checking and lubricating the brake and
clutch levers ........................................... 8-39
Checking the shift pedal ........................... 8-40
Checking and lubricating the brake pedal ....................................................... 8-40
Checking the wheel hub bearings ............ 8-40
Lubricating the swingarm pivots .............. 8-41
Lubricating the upper and lower arm pivots ...................................................... 8-41
Lubricating the steering shaft ................... 8-42UBW262E0.book Page 2 Tuesday, April 3, 2018 10:59 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
UBW262E0.book Page 2 Tuesday, April 3, 2018 10:59 AM

2-3
2
technique described in this manual on level
ground. Avoid crossing the side of a steep hill if
possible.
 Always use proper procedures if you stall or roll
backwards when climbing a hill. To avoid stall-
ing, use the proper gear and maintain a steady
speed when climbing a hill. If you stall or roll
backwards, follow the special procedure for
braking described in this manual. Dismount on
the uphill side or to a side if pointed straight up-
hill. Turn the ATV around and remount, following
the procedure described in this manual.
 Always check for obstacles before operating in
a new area.
 Never attempt to operate over large obstacles,
such as large rocks or fallen trees. Always follow
proper procedures when operating over obsta-
cles as described in this manual.
 Always be careful when skidding or sliding.
Learn to safely control skidding or sliding by
practicing at low speeds and on level, smooth
terrain. On extremely slippery surfaces, such as
ice, go slowly and be very cautious in order to
reduce the chance of skidding or sliding out of
control. 
Never operate an ATV in fast flowing water or in
water deeper than that recommended in this
manual. Remember that wet brakes may have
reduced stopping ability. Test your brakes after
leaving water. If necessary, apply them several
times to let friction dry out the linings.
 Always use the size and type of tires specified in
this manual.
 Always maintain proper tire pressure as de-
scribed in this manual.
 Never exceed the stated load capacity for an
ATV. Cargo should be properly distributed and
securely attached. Reduce speed and follow in-
structions in this manual for carrying cargo or
pulling a trailer. Allow greater distance for brak-
ing.
 Do not operate your ATV during darkness un-
less it is equipped with a properly functioning
headlight. Off-road riding is inherently danger-
ous and additionally, off-road trails do not have
streetlights to guide you.
 Never maintain an ATV without proper knowl-
edge. Contact an authorized ATV dealer to in-
form you on basic ATV maintenance. Certain
maintenance can only be carried out by certified
staff.
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5-1
5
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. 4-9, 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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8-1
8
EBU28788
PERIODIC MAINTENANCE AND ADJUSTMENT
EBU21677Periodic inspection, adjustment, and lubrication
will keep your vehicle in the safest and most effi-
cient condition possible. Safety is an obligation of
the vehicle owner and operator. The most impor-
tant points of vehicle inspection, adjustment, and
lubrication are explained on the following pages.
WARNING
EWB01842Failure to properly maintain the vehicle or per-
forming maintenance activities incorrectly may
increase your risk of injury or death during ser-
vice or while using the vehicle. If you are not fa-
miliar with vehicle service, have a Yamaha
dealer perform the service.
WARNING
EWB02563Turn off the engine when performing mainte-
nance unless otherwise specified.
A running engine has moving parts that can
catch on body parts or clothing and electri-
cal parts that can cause shocks or fires. 
Running the engine while servicing can lead
to eye injury, burns, fire, or carbon monoxide
poisoning - possibly leading to death. See
page 2-6 for more information about carbon
monoxide.

WARNING
EWB02691Brake discs, calipers, drums, and linings can
become very hot during use. To avoid possible
burns, let brake components cool before
touching them. The intervals given in the periodic maintenance
charts should be considered as a general guide
under normal riding conditions. However, DE-
PENDING ON THE WEATHER, TERRAIN, GEO-
GRAPHICAL LOCATION, AND INDIVIDUAL USE,
THE MAINTENANCE INTERVALS MAY NEED TO
BE SHORTENED.
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8
EBU29573Owner’s Manual and tool kitBe sure to always keep the Owner’s Manual, the
tool kit and the low-pressure tire gauge with the
vehicle. Make sure to protect the Owner’s Manual
by putting it in the plastic bag, then by placing the
bag in the document pouch.
The information included in this manual and the
tools provided in the tool kit are intended to assist
you in the performance of preventive maintenanceand minor repairs. However, additional tools such
as a torque wrench are necessary to perform cer-
tain maintenance work correctly.
TIPIf you do not have the tools or experience required
for a particular job, have a Yamaha dealer perform
it for you.
1. Owner’s Manual
2. Low-pressure tire gauge
3. Tool kit
1
2
3
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8
EBU21747Periodic maintenance chart: Emission control systemTIPFor ATVs not equipped with an odometer or an hour meter, follow the month maintenance intervals in-
stead.
 For odometer or hour meter-equipped vehicles, follow the month maintenance interval if the ATV isn’t
ridden for the stated mileage or engine operating hours.
 Items marked with an asterisk should be performed by a Yamaha dealer as they require special tools,
data and technical skills. NO. ITEM CHECK OR MAINTENANCE
JOB INITIAL
EVERY
Whichev-
er comes first month136612
km (mi) 320
(200) 1300
(800) 2500
(1600) 2500
(1600) 5000
(3200)
hours 20 80 160 160 320
1 *Fuel line • Check fuel hoses for cracks or other damage, and
replace if necessary. √√√
• Replace. Every 5 years
2 *Spark plug • Check condition and clean, regap, or replace if
necessary. √√√√√
3 *Va l ve s • Check valve clearance and adjust if necessary. √ √√√
4 *Crankcase breath-
er system • Check breather hose for cracks or other damage,
and replace if necessary. √√√
UBW262E0.book Page 3 Tuesday, April 3, 2018 10:59 AM