2009 YAMAHA YZ450F key

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.
When transporting the machine in
another vehicle, always be sure it is
properly secured and in an upright
position and that the fuel cock is in
the "OFF" position. Otherwise, fuel
may leak out of the carburetor or
fuel tank.
F.I.M. MACHINE WEIGHTS
Weights of machines without fuel
The minimum weights for motocross
machines are:
for the class 125 cc:
minimum 88 kg (194 lb)
for the class 250 cc:
minimum 98 kg (216 lb)
for the class 500 cc:
minimum 102 kg (225 lb)
In modifying your machine (e.g., for
weight reduction), take note of the
above limits of weight.

3-8
ENGINE
d. Tighten the locknut.
Before adjusting the throttle cable
free play, the engine idle speed
should be adjusted.
After adjusting the throttle cable
free play, start the engine and turn
the handlebar to right and left and
make sure that the engine idling
does not run faster.
LUBRICATING THE THROTTLE
1. Remove:
• Cover (throttle cable cap) "1"
• Cover (grip cap) "2"
• Throttle grip cap "3"
2. Apply:
• Lithium soap base grease
On the throttle cable end "a".
3. Install:
• Throttle grip cap
• Screw (throttle grip cap)
• Cover (grip cap)
• Cover (throttle cable cap)ADJUSTING THE HOT STARTER
LEVER FREE PLAY
1. Check:
• Hot starter lever free play "a"
Out of specification→Adjust.
2. Adjust:
• Hot starter lever free play
Hot starter lever free play adjust-
ment steps:
a. Loosen the locknut "1".
b. Turn the adjuster "2" until free
play "a" is within the specified lim-
its.
c. Tighten the locknut.
After adjustment, check proper oper-
ation of hot starter.
CLEANING THE AIR FILTER
ELEMENT
Proper air filter maintenance is the
biggest key to preventing premature
engine wear and damage.
Never run the engine without the
air filter element in place; this
would allow dirt and dust to enter
the engine and cause rapid wear
and possible engine damage.
1. Remove:
•Seat
• Fitting bolt "1"
•Washer "2"
• Air filter element "3"
• Air filter guide "4"2. Clean:
• Air filter element
Clean them with solvent.
After cleaning, remove the remaining
solvent by squeezing the element.
• Do not twist the element when
squeezing the element.
• Leaving too much of solvent in
the element may result in poor
starting.
3. Inspect:
• Air filter element
Damage→Replace.
4. Apply:
• Foam-air-filter oil or equivalent oil
to the element
Squeeze out the excess oil. Element
should be wet but not dripping.
5. Install:
• Air filter guide "1"
Align the projection "a" on filter guide
with the hole "b" in air filter element.
6. Apply:
• Lithium soap base grease
On the matching surface "a" on air
filter element. Locknut:
4 Nm (0.4 m•kg, 2.9
ft•lb)
Screw (throttle grip cap):
4 Nm (0.4 m•kg, 2.9
ft•lb)
Hot starter lever free play
"a":
3–6 mm (0.12–0.24 in)
Locknut:
4 Nm (0.4 m•kg, 2.9
ft•lb)

4-37
BALANCER
BALANCER
REMOVING THE BALANCER
Order Part name Q'ty Remarks
Primary driven gear Refer to "CLUTCH" section.
Right crankcase cover Refer to "OIL FILTER ELEMENT AND WA-
TER PUMP" section.
Stator Refer to "CDI MAGNETO" section.
1 Nut (balancer) 1 Refer to removal section.
2 Nut (primary drive gear) 1 Refer to removal section.
3 Nut (balancer shaft driven gear) 1 Refer to removal section.
4 Lock washer 1
5Balancer 1
6 Straight key 1
7 Conical washer 1
8 Primary drive gear 1
9 Balancer shaft drive gear 1
10 Lock washer 1
11 Balancer shaft driven gear 1

4-38
BALANCER
REMOVING THE BALANCER
1. Straighten the lock washer tab.
2. Loosen:
• Nut (balancer) "1"
• Nut (primary drive gear) "2"
• Nut (balancer shaft driven gear)
"3"
Place an aluminum plate "a" between
the teeth of the balancer shaft drive
gear "4" and driven gear "5".
CHECKING THE PRIMARY DRIVE
GEAR, BALANCER SHAFT DRIVE
GEAR AND BALANCER SHAFT
DRIVEN GEAR
1. Inspect:
• Primary drive gear "1"
• Balancer shaft drive gear "2"
• Balancer shaft driven gear "3"
Wear/damage→Replace.
CHECKING THE BALANCER
1. Inspect:
•Balancer
Cracks/damage→Replace.INSTALLING THE BALANCER
1. Install:
• Balancer shaft driven gear "1"
Install the balancer shaft driven gear
and balancer shaft with their lower
splines "a" aligning with each other.
2. Install:
• Balancer shaft driven gear "1"
• Align the punched mark "a" on the
balancer shaft drive gear with the
punched mark "b" on the balancer
shaft driven gear.
• Install the balancer shaft driven
gear and crankshaft with the lower
splines "c" aligning with each other.
3. Install:
• Lock washer "1"
• Nut (balancer shaft driven gear)
"2"
• Primary drive gear "3"
• Conical washer "4"
• Nut (primary drive gear) "5"
• Straight key "6"
• Balancer "7"
• Lock washer "8"• Nut (balancer) "9"
• Apply engine oil to the contact sur-
face and threaded portion of the nut
(primary drive gear).
• Place an aluminum plate "a" be-
tween the teeth of the balancer
shaft drive gear "10" and balancer
shaft driven gear "11".
• Install the conical washer with its
convex surface "b" outward.
4. Bend the lock washer tab.
Nut (balancer shaft driv-
en gear):
50 Nm (5.0 m•kg, 36
ft•lb)
Nut (primary drive gear):
110 Nm (11.0 m•kg, 80
ft•lb)
Nut (balancer):
45 Nm (4.5 m•kg, 33
ft•lb)

4-47
CDI MAGNETO
CDI MAGNETO
REMOVING THE CDI MAGNETO
Order Part name Q'ty Remarks
Seat and fuel tank Refer to "SEAT, FUEL TANK AND SIDE
COVERS" section.
Disconnect the CDI magneto lead.
1 Left crankcase cover 1
2Gasket 1
3 Dowel pin 2
4 Nut (rotor) 1 Refer to removal section.
5 Rotor 1 Refer to removal section.
6 Stator 1
7 Woodruff key 1

4-48
CDI MAGNETO
REMOVING THE ROTOR
1. Remove:
• Nut (rotor) "1"
• Washer
2. Remove:
• Rotor "1"
Use the rotor puller 2.
CHECKING THE CDI MAGNETO
1. Inspect:
• Rotor inner surface "a"
• Stator outer surface "b"
Damage→Inspect the crankshaft
runout and crankshaft bearing.
If necessary, replace CDI magne-
to and/or stator.
CHECKING THE WOODRUFF KEY
1. Inspect:
• Woodruff key "1"
Damage→Replace.
INSTALLING THE CDI MAGNETO
1. Install:
• Stator "1"
• Screw (stator) "2"
• Apply the sealant on the grommet
of the CDI magneto lead.
• Tighten the screws using the T30
bit.
2. Install:
• Woodruff key "1"
•Rotor "2"
• Degrease the contact surfaces of
the tapered portions of the crank-
shaft and rotor.
• When installing the woodruff key,
make sure that its flat surface "a" is
in parallel with the crankshaft center
line "b".
• When installing the rotor, align the
keyway "c" of the rotor with the
woodruff key.
3. Install:
•Washer
• Nut (rotor) "1"
4. Connect:
• CDI magneto lead
Refer to "CABLE ROUTING DIA-
GRAM" section in the CHAPTER
2.5. Install:
• Dowel pin
• O-ring
• Gasket (left crankcase cover)
• Left crankcase cover "1"
• Hose guide (cylinder head breath-
er hose) "2"
• Bolt (left crankcase cover)
• Apply the lithium soap base grease
on the O-ring.
• Tighten the bolts in stage, using a
crisscross pattern.
Rotor puller:
YM-04151/90890-04151
Screw (stator):
10 Nm (1.0 m•kg,
7.2ft•lb)
YAMAHA Bond No. 1215
(ThreeBond® No. 1215):
90890-85505
Nut (rotor):
56 Nm (5.6 m•kg, 40
ft•lb)
Bolt (left crankcase cov-
er):
10 Nm (1.0 m•kg, 7.2
ft•lb)