oil YAMAHA YZ450F 2014 Owners Manual

EAS1SL1005
SAFETY INFORMATION
THIS MACHINE IS DESIGNED STRICTLY FOR COMPETITION USE, ONLY ON A CLOSED
COURSE. It is illegal for this machine to be operated on any public street, road, or highway. Off-road
use on public lands may also be illegal. Please check local regulations before riding.
• THIS MACHINE IS TO BE OPERATED BY AN EXPERIENCED RIDER ONLY.
Do not attempt to operate this machine at maximum power until you are totally familiar with its char-
acteristics.
• THIS MACHINE IS DESIGNED TO BE RIDDEN BY THE OPERATOR ONLY.
Do not carry passengers on this machine.
• ALWAYS WEAR PROTECTIVE APPAREL.
When operating this machine, always wear an approved helmet with goggles or a face shield. Also
wear heavy boots, gloves, and protective clothing. Always wear proper fitting clothing that will not
be caught in any of the moving parts or controls of the machine.
• ALWAYS MAINTAIN YOUR MACHINE IN PROPER WORKING ORDER.
For safety and reliability, the machine must be properly maintained. Always perform the pre-oper-
ation checks indicated in this manual.
Correcting a mechanical problem before you ride may prevent an accident.
• GASOLINE IS HIGHLY FLAMMABLE.
Always turn off the engine while refueling. Take care to not spill any gasoline on the engine or ex-
haust system. Never refuel in the vicinity of an open flame, or while smoking.
• GASOLINE CAN CAUSE INJURY.
If you should swallow some gasoline, inhale excess gasoline vapors, or allow any gasoline to get
into your eyes, contact a doctor immediately. If any gasoline spills onto your skin or clothing, imme
-
diately wash skin areas with soap and water, and change your clothes.
• ONLY OPERATE THE MACHINE IN AN AREA WITH ADEQUATE VENTILATION.
Never start the engine or let it run for any length of time in an enclosed area. Exhaust fumes are
poisonous. These fumes contain carbon monoxide, which by itself is odorless and colorless. Car
-
bon monoxide is a dangerous gas which can cause unconsciousness or can be lethal.
• PARK THE MACHINE CAREFULLY; TURN OFF THE ENGINE.
Always turn off the engine if you are going to leave the machine. Do not park the machine on a slope
or soft ground as it may fall over.
• THE ENGINE, EXHAUST PIPE, MUFFLER, AND OIL TANK WILL BE VERY HOT AFTER THE EN-
GINE HAS BEEN RUN.
Be careful not to touch them or to allow any clothing item to contact them during inspection or repair.
• PROPERLY SECURE THE MACHINE BEFORE TRANSPORTING IT.
For safety, drain the gasoline from the fuel tank before transporting the vehicle.

EAS1SL1007
SYMBOLS
The following symbols are used in this manual for easier understanding.
TIP
The following symbols are not relevant to every vehicle.
SYMBOLDEFINITIONSYMBOLDEFINITION
Serviceable with engine mountedGear oil
Filling fluidMolybdenum disulfide oil
LubricantBrake fluid
Special toolWheel bearing grease
Tightening torqueLithium-soap-based grease
Wear limit, clearanceMolybdenum disulfide grease
Engine speedSilicone grease
Electrical dataLocking agent (LOCTITE®)
Engine oilReplace the part with a new one.
G
M
BF
B
T R..
LS
M
S
LT
E
New

1
GENERAL INFORMATION
LOCATION OF IMPORTANT LABELS............................................................ 1-1
DESCRIPTION .................................................................................................. 1-4
IDENTIFICATION ............................................................................................. 1-5
VEHICLE IDENTIFICATION NUMBER ...................................................... 1-5
ENGINE SERIAL NUMBER ....................................................................... 1-5
MODEL LABEL........................................................................................... 1-5
FEATURES ....................................................................................................... 1-6
OUTLINE OF THE FI SYST EM .................................................................. 1-6
FI SYSTEM....................................... .......................................................... 1-7
INCLUDED PARTS .......................................................................................... 1-8
SIDESTAND ............................................................................................... 1-8
SPARK PLUG WRENCH ........................................................................... 1-8
NIPPLE WRENCH...................................................................................... 1-8
HANDLEBAR PROTECTOR .. .................................................................... 1-8
FUEL HOSE JOINT COVER ...................................................................... 1-8
COUPLER FOR CONNECTING OPTIONAL PART................................... 1-8
IMPORTANT INFORMATION ........................................................................ 1-10
PREPARATION FOR REMOVAL A ND DISASSEMBLY.......................... 1-10
REPLACEMENT PARTS.......................................................................... 1-10
GASKETS, OIL SEALS AND O-RINGS ................................................... 1-11
LOCK WASHERS/PLATES AND COTTER PINS .................................... 1-11
BEARINGS AND OIL SEALS ................................................................... 1-11
CIRCLIPS ................................................................................................. 1-11
BASIC SERVICE INFORMATION .................................................................. 1-12
ELECTRICAL SYSTEM.......... .................................................................. 1-12
SPECIAL TOOLS ........................................................................................... 1-15
CONTROL FUNCTIONS ................................................................................ 1-20
ENGINE STOP SWITCH .......................................................................... 1-20
CLUTCH LEVER ................................................................................... ... 1-20
SHIFT PEDAL .......................................................................................... 1-20
KICKSTARTER LEVER.......... .................................................................. 1-20
THROTTLE GRIP ..................................................................................... 1-20
FRONT BRAKE LEVER ........................................................................... 1-20
REAR BRAKE PEDAL.............................................................................. 1-21
STARTER KNOB/IDLE SCREW .............................................................. 1-21
FUEL TANK CAP ..................................................................................... 1-21

DESCRIPTION
1-4
EAS1SL1009
DESCRIPTION
TIP
Designs and specifications of the vehicle are subject to change without notice. Therefore, please
note that the descriptions in this manual may be different from those for the vehicle you have pur
-
chased.
1. Clutch lever10. Coolant drain bolt
2. Front brake lever11. Rear brake pedal
3. Throttle grip12. Air filter
4. Radiator cap13. Drive chain
5. Fuel tank cap14. Shift pedal
6. Engine stop switch15. Oil level check window
7. Fuel tank16. Starter knob/idle screw
8. Kickstarter lever17. Front fork
9. Radiator
2 1
6
78 954 3
11 10 17 16 15 14 1312

FEATURES
1-6
EAS20170
FEATURES
EAS1SL1014OUTLINE OF THE FI SYSTEM
The main function of a fuel supply system is to provide fuel to the combustion chamber at the opti-
mum air-fuel ratio in accordance with the engine operating conditions and the atmospheric tempera-
ture. In the conventional carburetor system, the air-fuel ratio of the mixture to be supplied to the
combustion chamber is determined by the amount of intake air and fuel that is measured on the basis
of the jets to be used in the carburetor.
Despite the same amount of intake air, the fuel amount requirement varies with the engine operating
conditions (acceleration, deceleration, and operation under a heavy load). The carburetor that mea
-
sures fuel through the use of jets are provided with various auxiliary devices, so that the optimum air
fuel ratio can be obtained to accommodate frequent changes in the operating conditions of the en
-
gine. This model has adopted an electronically controlled fuel injection (FI) system, in place of the
conventional carburetor system. This system can obtain the optimum air-fuel ratio required by the
engine at all times by using a microprocessor that regulates the fuel injection amount according to
the engine operating conditions detected by various sensors.
EAS1SL1015
1. Fuel injector
2. Throttle position sensor
3. Intake air pressure sensor
4. Intake air temperature sensor
5. ECU
6. Fuel pump
7. Condenser
8. Crankshaft position sensor
9. Coolant temperature sensor
10.Ignition coil
6
7 8 95 4 123
10

IMPORTANT INFORMATION
1-10
EAS20180
IMPORTANT INFORMATION
EAS1SL1023PREPARATION FOR REMOVAL AND DIS-
ASSEMBLY
1. Before the jobs, completely remove mud,
dust, and the like in order to prevent the en
-
try of them into the inside during the jobs.
• Before cleaning with high-pressure water of
washers, cover the following parts.

Air duct
Silencer exhaust port
Drain hole on the cylinder head (right side)
Hole under the water pump housing
2. Use proper special tools and equipment.
See “SPECIAL TOOLS.”
3. During disassembly, check and measure the
required parts, and make a record of them
so that you may refer to the record when in
-
stalling them. Moreover, arrange gears, cyl-
inders, pistons, and other parts for each
section so as not to confuse or lose them.
4. During disassembly, clean each of the parts,
and store them in trays for each section.
5. Flammable. Keep servicing areas away
from any source of fire.
6. During servicing, take special care not to re-
ceive an injury or a burn on the engine, the
exhaust pipe, the silencer, or the like.
7. If coolant is left adhered to the chassis, paint
and plating will be damaged. Therefore,
rinse it out with water in good time.
EWA
WARNING
Coolant is potentially harmful and should
be handled with special care.
• If it enters your eyes, wash it away with wa-
ter enough and then get medical attention
• If it splashes on your skin or clothes,
quickly wash it away with water and then
with soapy water.
• If it is swallowed, immediately induce vom-
iting and get medical attention.
EAS1SL1024REPLACEMENT PARTS
Make sure that the parts and grease or oil to be
used for repair of the vehicle, including periodic
replacement parts, are new YAMAHA genuine
parts and recommended parts.
Do not use any used parts, because these may
not be genuine though they have similar ap
-
pearances or because the quality may be
changed by aging.
EAS1SL1025

IMPORTANT INFORMATION
1-11
GASKETS, OIL SEALS AND O-RINGS
1. When overhauling the engine, replace all
gaskets and O-rings. All gasket surfaces, oil
seal lips, and O-rings must be cleaned so
that there may be no dust on them.
2. During assembly, always apply proper oil to
bearings and proper grease to oil seal lips
before installation.
EAS1SL1026LOCK WASHERS/PLATES AND COTTER
PINS
After removal, replace lock washers/plates “1”
and cotter pins with new ones. After the bolt or
nut has been tightened to specification, firmly
bend the lock tabs along a flat of the bolt or nut.
EAS1SL1027BEARINGS AND OIL SEALS
Install bearings “1” and oil seals “2” with their
manufacturer’s marks or size symbols facing
outward. During installation of an oil seal, make
sure that its main lip faces the oil chamber (the
target to be sealed). Before installation, always
apply a light coat of grease to the oil seal lip.
ECA13300
NOTICE
Do not spin a bearing with compressed air
because this will damage the bearing sur
-
faces.
EAS1SL1028CIRCLIPS
When assembling parts, always use new cir-
clips. During installation of a circlip, make sure
that the edge “2” of the circlip “1” is positioned
opposite to the force “3” that the circlip re
-
ceives. Install the circlip with its end aligned
with the center of the spline, without opening
the circlip more than necessary.
1. Oil
2. Lip
3. Spring
4. Grease

SPECIAL TOOLS
1-16
Radiator cap tester
90890-01325
Mityvac cooling system tester
kit
YU-24460-A
This tool is used to check the
radiator and the radiator cap.
Radiator cap tester adapter
90890-01352
Pressure tester adapter
YU-33984
This tool is used to check the
radiator and the radiator cap.
Steering nut wrench
90890-01403
Exhaust flange nut wrench
YU-A9472
This tool is used to remove or
tighten the steering nut.
Cap bolt wrench
90890-01500
YM-01500
This tool is used to remove or
tighten the base valve.
Cap bolt ring wrench
90890-01501
YM-01501
This tool is used to loosen or
tighten the damper assem
-
bly.
Fork seal driver
90890-01502
YM-A0948
This tool is used to install the
oil seal of the front fork.
Spoke nipple wrench (6–7)
90890-01521
YM-01521
This tool is used to tighten the
spoke.
Tool name/Part number How to use Illustration

SPECIAL TOOLS
1-19
Crankcase separating tool
90890-04152
YU-A9642
This tool is used to remove
the crankshaft.
Ignition checker
90890-06754
Oppama pet-4000 spark
checker
YM-34487
This tool is used to check the
spark performance of the ig
-
nition coil.
Digital tachometer
90890-06760
YU-39951-B
This tool is used to measure
the engine speed.
Three bond No.1215®
90890-85505
This sealant (Bond) is used
for crankcase mating sur
-
face, etc.
Tool name/Part number How to use Illustration

STARTING AND BREAK-IN
1-23
7. To stop the engine, push the engine stop
switch “1.”
TIP
Continue pushing the engine stop switch till the
engine comes to a full stop.
EAS1SL1044STARTING A WARM ENGINE
When the engine is warm, give a kick with the
throttle closed without using the starter knob/
idle screw.
TIP
If it fails to start, fully open the throttle grip and
give 10 to 20 slow kicks to clear the engine of
the rich air-fuel mixture retained in it.
EAS1SL1045BREAK-IN PROCEDURES
A break-in is important so that rotating portion,
sliding surfaces, and mounted areas may fit
one another, and that the rider may become ac
-
customed to the machine.ECA
NOTICE
Before running, do maintenance on the air
filter element.
Refer to “CLEANING THE AIR FILTER ELE-
MENT” on page 3-12.
1. After warming up the engine, drive it for
about 20 minutes at a throttle opening of 1/2
or less.
2. Make a pit stop, and check mounted areas
for looseness, oil leaks, or other problems.
3. Then, drive it for about 40 minutes at a throt-
tle opening of 3/4 or less.
4. Make a pit stop again, and thoroughly check
mounted areas for looseness, oil leaks, or
other problems. Thorough checks and ad
-
justments are required in particular for
stretch of cables, free play of the brake,
stretch of the drive chain, looseness of the
spoke, and so on.
ECA
NOTICE
After a break-in or after each race, always
check the points shown in “TORQUE-
CHECK POINTS” for tightening torques and
retighten them. (
“TORQUE-CHECK
POINTS” on page 1-25) 
Also when the following parts are replaced,
a break-in is required.
• Cylinder and Crankshaft: A break-in is re-
quired for about an hour.
• Piston, Piston ring, Valve, Camshaft, and
Gear: A break-in is required for about 30
minutes at a throttle opening of 1/2 or less.
Observe the condition of the engine careful-
ly during a break-in. 
For checkpoints for a break-in, see “MAIN-
TENANCE AFTER BREAK-IN.” If any prob-
lem is found, immediately stop the engine
and make a checkup.
EAS1SL1046