2013 YAMAHA YZ450F change time

FOREWORD
INTRODUCTION
Congratulations on your purchase of
a Yamaha YZ series. This model is
the culmination of Yamaha's vast ex-
perience in the production of paceset-
ting racing machines. It represents
the highest grade of craftsmanship
and reliability that have made Yama-
ha a leader.
This manual explains operation, in-
spection, basic maintenance and tun-
ing of your machine. If you have any
questions about this manual or your
machine, please contact your Yama-
ha dealer.
Yamaha continually seeks advance-
ments in product design and quality.
Therefore, while this manual contains
the most current product information
available at the time of printing, there
may be minor discrepancies between
your machine and this manual. If you
have any questions concerning this
manual, please consult your Yamaha
dealer.
PLEASE READ THIS MANUAL
CAREFULLY AND COMPLETELY
BEFORE OPERATING THIS MA-
CHINE. DO NOT ATTEMPT TO OP-
ERATE THIS MACHINE UNTIL YOU
HAVE ATTAINED A SATISFACTO-
RY KNOWLEDGE OF ITS CON-
TROLS AND OPERATING
FEATURES AND UNTIL YOU HAVE
BEEN TRAINED IN SAFE AND
PROPER RIDING TECHNIQUES.
REGULAR INSPECTIONS AND
CAREFUL MAINTENANCE,
ALONG WITH GOOD RIDING
SKILLS, WILL ENSURE THAT YOU
SAFETY ENJOY THE CAPABILI-
TIES AND THE RELIABILITY OF
THIS MACHINE.
IMPORTANT MANUAL
INFORMATION
Particularly important information is
distinguished in this manual by the
following notations.
This is the safety alert symbol. It is
used to alert you to potential per-
sonal injury hazards. Obey all safe-
ty messages that follow this
symbol to avoid possible injury or
death.
A WARNING indicates a hazardous
situation which, if not avoided,
could result in death or serious in-
jury.
A NOTICE indicates special pre-
cautions that must be taken to
avoid damage to the vehicle or oth-
er property.
A TIP provides key information to
make procedures easier or clearer.
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 OPER-
ATED BY AN EXPERIENCED RID-
ER ONLY.
Do not attempt to operate this ma-
chine at maximum power until you
are totally familiar with its character-
istics.
• 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, al-
ways 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 MA-
CHINE IN PROPER WORKING
ORDER.
For safety and reliability, the ma-
chine must be properly maintained.
Always perform the pre-operation
checks indicated in this manual.
Correcting a mechanical problem
before you ride may prevent an ac-
cident.
• GASOLINE IS HIGHLY FLAMMA-
BLE.
Always turn off the engine while re-
fueling. Take care to not spill any
gasoline on the engine or exhaust
system. Never refuel in the vicinity
of an open flame, or while smoking.
• GASOLINE CAN CAUSE INJURY.
If you should swallow some gaso-
line, inhale excess gasoline vapors,
or allow any gasoline to get into
your eyes, contact a doctor immedi-
ately. If any gasoline spills onto
your skin or clothing, immediately
wash skin areas with soap and wa-
ter, 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 poison-
ous. These fumes contain carbon
monoxide, which by itself is odor-
less and colorless. Carbon monox-
ide is a dangerous gas which can
cause unconsciousness or can be
lethal.
• PARK THE MACHINE CAREFUL-
LY; 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 MA-
CHINE BEFORE TRANSPORTING
IT.
For safety, drain the gasoline from
the fuel tank before transporting the
vehicle.

1-7
FEATURES
FEATURES
OUTLINE OF THE FI SYSTEM
The main function of a fuel supply system is to provide fuel to the combustion chamber at the optimum air-fuel ratio in ac-
cordance with the engine operating conditions and the atmospheric temperature. In the conventional carburetor system,
the air-fuel ratio of the mixture that is supplied to the combustionchamber is created by the volume of the intake air and the
fuel that is metered by the jet used in the respective carburetor.
Despite the same volume of intake air, the fuel volume requirement varies by the engine operating conditions,such as ac-
celeration, deceleration, or operating under a heavy load. Carburetors that meter thefuel through the use of jets have been
provided with various auxiliary devices, so that an optimum air-fuel ratio can be achieved to accommodate the constant
changes in the operating conditions of the engine.
This model has adopted an electronically controlled fuel injection (FI) system, in place of the conventional carburetor sys-
tem. This system can achieve an optimum air-fuel ratio required bythe engine at all times by using a microprocessor that
regulates the fuel injection volume according tothe engine operating conditions detected by various sensors.
1. Fuel injector
2. Throttle position sensor
3. Intake air pressure sensor
4. ECU
5. Fuel pump
6. Intake air temperature sensor7. Atmospheric pressure sensor
8. Crankshaft position sensor
9. Coolant temperature sensor
10. Ignition coil
11. Condenser

7-11
FUEL INJECTION SYSTEM
SENSOR OPERATION TABLE
Diagnos-
tic code
No.ItemActuation or
displayChecking methodActuation or LCD standard display
values
D01 Throttle angle DisplayDisplays the throttle angle. 0–125°
Check with throttle fully closed. When throttle is fully closed:15–19°
Check with throttle fully open. When throttle is fully opened:95–
101 °
D02 Atmosphere DisplayDisplays the atmospheric pres-
sure.
• Measure the atmospheric pres-
sure.0–126 kPa
Displays the atmospheric pressure
according to the elevation and
weather.
Example
0 m above sea level: Approx: 101
kPa
3000 m above sea level:Approx: 70
kPa
D03 Intake air pressure DisplayDisplays the intake air pressure.
• Check the intake manifold pres-
sure.
• Check that the intake air pres-
sure changes while the engine is
being cranked.0–126 kPa
While the engine is stopped: Dis-
plays the atmospheric pressure ac-
cording to the elevation and
weather.
Example
0 m above sea level: Approx: 101
kPa
3000 m above sea level:Approx: 70
kPa
While the engine is being cranked:
Displays the intake air pressure.
D05 Intake air temperature DisplayDisplays the intake air tempera-
ture.
• Check the temperature in the in-
take manifold.-20–100°C
Cold engine: Displayed tempera-
ture is close to the ambient temper-
ature.
Warm engine: Displayed tempera-
ture is approximately 20 °C higher
than the ambient temperature.
D06 Coolant temperature DisplayDisplays the coolant temperature.
• Check the coolant temperature.-20–150°C
Cold engine: Displayed tempera-
ture is close to the ambient temper-
ature.
Warm engine: Displayed tempera-
ture is the current coolant tempera-
ture.
D08 Lean angle sensor DisplayDisplays the lean angle sensor
output voltage.
Remove the ECU and incline it 45°
or more.0–5.0 V
1.0 V: Upright
4.0 V: Overturned
D30 Ignition coil ActuationCheck that power is supplied to
the ignition coil.
• Check that a spark is generated.
• Illuminates the engine trouble
warning light.Actuates the ignition coil for five
times every second.
The "WARNING" LED on the FI di-
agnostic tool comes on each time
the fuel injector is actuated.

8-1
CHASSIS
TUNING
CHASSIS
SELECTION OF THE SECONDARY
REDUCTION RATIO (SPROCKET)
ondary gear reduction ratio>
• It is generally said that the second-ary gear ratio should be reduced for
a longer straight portion of a speed
course and should be increased for
a course with many corners. Actual-
ly, however, as the speed depends
on the ground condition of the day
of the race, be sure to run through
the circuit to set the machine suit-
able for the entire course.
• In actuality, it is very difficult to achieve settings suitable for the en-
tire course and some settings may
be sacrificed. Thus, the settings
should be matched to the portion of
the course that has the greatest ef-
fect on the race result. In such a
case, run through the entire course
while making notes of lap times to
find the best balance; then, deter-
mine the secondary reduction ratio.
• If a course has a long straight por- tion where a machine can run at
maximum speed, the machine is
generally set such that it can devel-
op its maximum revolutions toward
the end of the straight line, with care
taken to avoid the engine over-rev-
ving.
Riding technique varies from rider to
rider and the performance of a ma-
chine also vary fr om machine to ma-
chine. Therefore, do not imitate other
rider's settings from the beginning but
choose your own setting according to
the level of your riding technique.
DRIVE AND REAR WHEEL
SPROCKETS SETTING PARTS
TIRE PRESSURE
Tire pressure should be adjust to suit
the road surface condition of the cir-
cuit.
• Under a rainy, muddy, sandy, or slippery condition, the tire pressure
should be lower for a larger area of
contact with the road surface.
• Under a stony or hard road condi- tion, the tire pressure should be
higher to prevent a flat tire. FRONT FORK SETTING
The front fork setting should be made
depending on the rider's feeling of an
actual run and the circuit conditions.
The front fork setting includes the fol-
lowing three factors:
1. Setting of air spring characteris-
tics
• Change the fork oil amount.
2. Setting of spring preload
• Change the spring.
3. Setting of damping force • Change the compression damp-
ing.
• Change the rebound damping. The spring acts on the load and
the damping force acts on the
cushion travel speed.
CHANGE IN AMOUNT AND
CHARACTERISTICS OF FORK OIL
Damping characteristic near the final
stroke can be changed by changing
the fork oil amount.
Adjust the oil amount in 5 cm3 (0.2
Imp oz, 0.2 US oz) increments or
decrements. Too small oil amount
causes the front fork to produce a
noise at full rebound or the rider to
feel some pressure on his hands
or body. Alternatively, too large oil
amount will cause the air spring
characteristics to have a tendency
to be stiffer with the consequent
deteriorated performance and
characteristics. Therefore, adjust
the front fork within the specified
range.
Secondary reduction ratio = Number of rear wheel sprocket
teeth/Number of drive sprocket
teeth
Standard secondary
reduction ratio 3.692
(48/13)
* 3.769
(49/13)
* Except for USA and CDN
Part name Size Part number
Drive
sprocket "1" (STD) 13T 9383E-13233
Rear wheel
sprocket "2" 47T 17D-25447-50
(STD) 48T 17D-25448-50
* (STD) 49T 17D-25449-50 50T 17D-25450-50
51T 17D-25451-50
52T 17D-25452-50
* Except for USA and CDN
Standard tire pressure:100 kPa (1.0 kgf/cm
2,
15 psi)
Extent of adjustment: 60–80 kPa (0.6–0.8 kgf/
cm
2, 9.0–12 psi)
Extent of adjustment: 100–120 kPa (1.0–1.2
kgf/cm
2, 15–18 psi)
Standard oil amount:
355 cm3 (12.5 Imp oz,
12.0 US oz)
Extent of adjustment:
300–365 cm
3 (10.6–12.8
Imp oz, 10.1–12.3 US
oz)