2009 YAMAHA WR 450F light

3-27
CHASSIS
4. Adjust:
• Steering ring nut
Steering ring nut adjustment
steps:
a. Remove the headlight.
b. Remove the handlebar and upper
bracket.
c. Loosen the steering ring nut "1"
using the steering nut wrench "2".
d. Tighten the steering ring nut "3"
using steering nut wrench "4".
• Apply the lithium soap base grease
on the thread of the steering stem.
• Set the torque wrench to the steer-
ing nut wrench so that they form a
right angle.
e. Loosen the steering ring nut one
turn.
f. Retighten the steering ring nut us-
ing the steering nut wrench.
Avoid over-tightening.
g. Check the steering stem by turn-
ing it lock to lock. If there is any
binding, remove the steering stem
assembly and inspect the steer-
ing bearings.
h. Install the washer "5", upper
bracket "6", washer "7", steering
stem nut "8", handlebar "9", han-
dlebar upper holder "10" and
headlight "11".
• The handlebar upper holder should
be installed with the punched mark
"a" forward.
• Install the handlebar so that the
marks "b" are in place on both
sides.
• Install the handlebar so that the pro-
jection "c" of the handlebar upper
holder is positioned at the mark on
the handlebar as shown.
• Insert the end of the fuel breather
hose "12" into the hole in the steer-
ing stem.
First tighten the bolts on the front
side of the handlebar upper holder,
and then tighten the bolts on the
rear side.
Steering nut wrench:
YU-33975/90890-01403
Steering nut wrench:
YU-33975/90890-01403
Steering ring nut (initial
tightening):
38 Nm (3.8 m•kg, 27
ft•lb)
Steering ring nut (final
tightening):
7 Nm (0.7 m•kg, 5.1
ft•lb)
Steering stem nut:
145 Nm (14.5 m•kg, 105
ft•lb)
Handlebar upper holder:
28 Nm (2.8 m•kg, 20
ft•lb)
Pinch bolt (upper brack-
et):
21 Nm (2.1 m•kg, 15
ft•lb)
Headlight:
7 Nm (0.7 m•kg, 5.1
ft•lb)

3-28
CHASSIS
LUBRICATION
To ensure smooth operation of all
components, lubricate your machine
during setup, after break-in, and after
every ride.
1. All control cable
2. Clutch lever pivot
3. Shift pedal pivot
4. Footrest pivot
5. Throttle-to-handlebar contact
6. Drive chain
7. Tube guide cable winding por-
tion
8. Throttle cable end
9. Clutch cable end
10. Hot starter cable endA. Use Yamaha cable lube or
equivalent on these areas.
B. Use SAE 10W-30 motor oil or
suitable chain lubricants.
C. Lubricate the following areas
with high quality, lightweight lith-
ium-soap base grease.
Wipe off any excess grease, and
avoid getting grease on the brake
discs.

3-29
ELECTRICAL
ELECTRICAL
CHECKING THE SPARK PLUG
1. Remove:
• Spark plug
2. Inspect:
• Electrode "1"
Wear/damage→Replace.
• Insulator color "2"
Normal condition is a medium to
light tan color.
Distinctly different color→Check
the engine condition.
When the engine runs for many hours
at low speeds, the spark plug insula-
tor will become sooty, even if the en-
gine and carburetor are in good
operating condition.
3. Measure:
• Plug gap "a"
Use a wire gauge or thickness
gauge.
Out of specification→Regap.
4. Clean the plug with a spark plug
cleaner if necessary.
5. Tighten:
• Spark plug
• Before installing a spark plug, clean
the gasket surface and plug sur-
face.
• Finger-tighten "a" the spark plug
before torquing to specification "b".
CHECKING THE IGNITION TIMING
1. Remove:
• Timing mark accessing screw "1"
2. Attach:
• Timing light
• Digital tachometer
To the ignition coil lead (orange
lead"1").
3. Adjust:
• Engine idling speed
Refer to "ADJUSTING THE EN-
GINE IDLING SPEED" section.
4. Check:
• Ignition timing
Visually check the stationary
pointer "a" is within the firing
range "b" on the rotor.
Incorrect firing range→Check ro-
tor and pickup assembly.
5. Install:
• Timing mark accessing screw
CHECKING AND CHARGING THE
BATTERY
Batteries generate explosive hy-
drogen gas and contain electrolyte
which is made of poisonous and
highly caustic sulfuric acid. There-
fore, always follow these preven-
tive measures:
• Wear protective eye gear when
handling or working near batter-
ies.• Charge batteries in a well-venti-
lated area.
• Keep batteries away from fire,
sparks or open flames (e.g.,
welding equipment, lighted ciga-
rettes).
• DO NOT SMOKE when charging
or handling batteries.
• KEEP BATTERIES AND ELEC-
TROLYTE OUT OF REACH OF
CHILDREN.
• Avoid bodily contact with elec-
trolyte as it can cause severe
burns or permanent eye injury.
FIRST AID IN CASE OF BODILY
CONTACT:
EXTERNAL
• Skin — Wash with water.
• Eyes — Flush with water for 15
minutes and get immediate med-
ical attention.
INTERNAL
• Drink large quantities of water or
milk followed with milk of magne-
sia, beaten egg or vegetable oil.
Get immediate medical attention.
Charging time, charging amperage
and charging voltage for an MF
battery are different from those of
conventional batteries. The MF
battery should be charged as ex-
plained in the charging method il-
lustrations. If the battery is
overcharged, the electrolyte level
will drop considerably. Therefore,
take special care when charging
the battery.
Since MF batteries are sealed, it is
not possible to check the charge state
of the battery by measuring the spe-
cific gravity of the electrolyte. There-
fore, the charge of the battery has to
be checked by measuring the voltage
at the battery terminals.
1. Remove:
• Seat
2. Disconnect:
• Battery leads
(from the battery terminals)
First, disconnect the negative bat-
tery lead "1", and then the positive
battery lead "2".
Spark plug gap:
0.7–0.8 mm (0.028–
0.031 in)
Spark plug:
13 Nm (1.3 m•kg, 9.4
ft•lb)
Timing light:
YM-33277-A/90890-
03141

3-33
ELECTRICAL
6. Install:
•Battery
• Battery band
7. Connect:
• Battery leads
(to the battery terminals)
First, connect the positive lead "1",
then the negative lead "2".
8. Check:
• Battery terminals
Dirt→Clean with a wire brush.
Loose connection→Connect
properly.
9. Lubricate:
• Battery terminal
10. Install:
• Seat
CHECKING THE FUSE
To avoid a short circuit, always set
the main switch to "OFF" when
checking or replacing a fuse.
1. Remove:
• Seat
• Fuse cover
2. Check:
• Continuity
Checking steps:
a. Remove the fuse "1".
b. Connect the pocket tester to the
fuse and check the continuity.
Set the pocket tester selector to " Ω×
1".
2. Reserve fuse
c. If the pocket tester indicates "∞",
replace the fuse.
3. Replace:
• Blown fuse
Replacement steps:
a. Set the main switch to "OFF".
b. Install a new fuse of the correct
amperage.
c. Set on the switches to verify if the
electrical circuit is operational.
d. If the fuse immediately blows
again, check the electrical circuit.
Never use a fuse with an amperage
rating other than that specified. Im-
provising or using a fuse with the
wrong amperage rating may cause
extensive damage to the electrical
system, cause the starting and ig-
nition systems to malfunction and
could possibly cause a fire.
4. Install:
• Fuse cover
•Seat
REPLACING THE HEADLIGHT
BULBS
1. Remove:
• Headlight
Refer to "REMOVING THE SEAT,
FUEL TANK AND SIDE COV-
ERS" section.2. Remove:
• Headlight bulb holder cover "1"
3. Remove:
• Headlight bulb holder "1"
Remove the headlight bulb holder by
pushing it in and turning it counter-
clockwise.
4. Remove:
• Headlight bulb
Since the headlight bulb gets ex-
tremely hot, keep flammable prod-
ucts and your hands away from the
bulb unit it has cooled down.
5. Install:
• Headlight bulb
Avoid touching the glass part of
the headlight bulb to keep it free
form oil, otherwise the transparen-
cy of the glass, the life of the bulb
and the luminous flux will be ad-
versely affected. If the headlight
bulb gets soiled, thoroughly clean
it with a cloth moistened with alco-
hol or lacquer thinner.
6. Install:
• Headlight bulb holder
7. Install:
• Headlight bulb holder cover
8. Install:
• Headlight
Refer to "REMOVING THE SEAT,
FUEL TANK AND SIDE COV-
ERS" section. Recommended lubricant:
Lithium soap base
grease
Pocket tester:
YU-3112-C/90890-
03112
Items Amperage
ratingQ'ty
Main fuse 10 A 1
Headlight:
7 Nm (0.7 m•kg, 5.1
ft•lb)

3-34
ELECTRICAL
ADJUSTING THE HEADLIGHT
BEAMS
1. Adjust:
• Headlight beam (vertically)
Adjusting steps:
a. Turn the adjusting screw "1" in di-
rection "a" or "b".
Direction "a" Headlight beam is
raised.
Direction "b" Headlight beam is
lowered.

4-1
ENGINE (Except for Canada)
TUNING
ENGINE (Except for Canada)
CARBURETOR SETTING
• The air/fuel mixture will vary de-
pending on atmospheric conditions.
Therefore, it is necessary to take
into consideration the air pressure,
ambient temperature, humidity,
etc., when adjusting the carburetor.
• Perform a test run to check for prop-
er engine performance (e.g., throt-
tle response) and spark plug(-s)
discoloration or fouling. Use these
readings to determine the best pos-
sible carburetor setting.
It is recommended to keep a record of
all carburetor settings and external
conditions (e.g., atmospheric condi-
tions, track/surface conditions, lap
times) to make future carburetor set-
ting easier.
• The carburetor is a part of the
fuel line. Therefore, be sure to in-
stall it in a wellventilated area,
away from flammable objects
and any sources of fire.
• Never look into the carburetor in-
take. Flames may shoot out from
the pipe if the engine backfires
while it is being started. Gasoline
may be discharged from the ac-
celerator pump nozzle when the
carburetor has been removed.
• The carburetor is extremely sen-
sitive to foreign matter (dirt,
sand, water, etc.). During instal-
lation, do not allow foreign mat-
ter to get into the carburetor.
• Always handle the carburetor
and its components carefully.
Even slight scratches, bends or
damage to carburetor parts may
prevent the carburetor from
functioning correctly. Carefully
perform all servicing with the ap-
propriate tools and without ap-
plying excessive force.
• When the engine is stopped or
when riding at no load, do not
open and close the throttle un-
necessarily. Otherwise, too
much fuel may be discharged,
starting may become difficult or
the engine may not run well.• After installing the carburetor,
check that the throttle operates
correctly and opens and closes
smoothly.
ATMOSPHERIC CONDITIONS AND
CARBURETOR SETTINGS
The air density (i.e., concentration of
oxygen in the air) determines the rich-
ness or leanness of the air/fuel mix-
ture.
• Higher temperature expands the air
with its resultant reduced density.
• Higher humidity reduces the
amount of oxygen in the air by so
much of the water vapor in the
same air.
• Lower atmospheric pressure (at a
high altitude) reduces the density of
the air.
EFFECT OF SETTING PARTS IN
RELATION TO THROTTLE VALVE
OPENING
A. Closed
B. Fully open
1. Pilot jet
2. Throttle valve cutaway
3. Jet needle
4. Main jetCONSTRUCTION OF
CARBURETOR AND SETTING
PARTS
The FLATCR carburetor has a prima-
ry main jet. This type of main jet is
perfect for racing machines since it
supplies an even flow of fuel, even at
full load. Use the main jet and the jet
needle to set the carburetor.
1. Jet needle
2. Pilot air jet
3. Needle jet
4. Main jet
5. Pilot jet
ADJUSTING THE MAIN JET
The richness of the air-fuel mixture at
full throttle can be set by changing the
main jet "1".
If the air-fuel mixture is too rich or too
lean, the engine power will drop, re-
sulting in poor acceleration.
Effects of changing the main jet
(reference)
A. Idle
B. Fully open
1. #165
2. #160
3. #162 Air
tem
p.Hu-
midi-
tyAir
pres-
sure
(alti-
tude)Mix-
tureSet-
ting
High HighLow
(high)Rich-
erLean-
er
Low LowHigh
(low)Lean-
erRich-
er
Standard main jet#162
* #160
* For EUROPE

5-10
CARBURETOR
• Apply the fluorochemical grease on
the bearings.
• Fit the projection "a" on the throttle
shaft assembly into the slot "b" in
the throttle position sensor.
• Make sure the stopper "c" of the
spring fits into the recess in the car-
buretor.
• Turn the throttle shaft assembly left
while holding down the lever 1 "5"
and fit the throttle stop screw tip "d"
to the stopper "e" of the throttle
shaft assembly pulley.
9. Install:
• Push rod "1"
While holding down the lever 1 "2", in-
sert the push rod farthest into the car-
buretor.
10. Install:
• Starter jet "1"
• Pilot jet "2"
• Spacer "3"
• Needle jet "4"
•Main jet "5"
11. Install:
• Needle valve "1"
•Float "2"
• Float pin "3"
• After installing the needle valve to
the float, install them to the carbure-
tor.
• Check the float for smooth move-
ment.
12. Install: (For EUROPE)
• Pilot screw "1"
• Spring "2"
• Washer "3"
• O-ring "4"
Note the following installation
points:
a. Turn in the pilot screw until it is
lightly seated.
b. Turn out the pilot screw by the
number of turns recorded before
removing.
13. Install:
• O-ring
• Leak jet "1"
• Float chamber "2"
• Bolt (float chamber) "3"
• Cable holder (throttle stop screw
cable) "4"
• Hose holder (carburetor breather
hose) "5"
14. Install:
• Diaphragm (air cut valve) "1"
• Spring (air cut valve) "2"
• O-ring "3"
• Air cut valve cover "4"
• Holder (cylinder head breather
hose) "5"
• Screw (air cut valve cover) "6"
15. Install:
• Diaphragm (accelerator pump)
"1"
• Spring "2"
• O-ring "3"
• Accelerator pump cover "4"
• Hose holder (drain hose) "5"
• Screw (accelerator pump cover)
"6"
Install the diaphragm (accelerator
pump) with its mark "a" facing the
spring.
Pilot screw (example):
2 turns out

5-11
CARBURETOR
16. Install:
• Jet needle "1"
•Collar "2"
• Spring "3"
• Needle holder "4"
• Throttle valve plate "5"
To throttle valve "6".
17. Install:
• Throttle valve assembly "1"
• Screw (throttle shaft) "2"
Install the valve lever rollers "3" into
the slits "a" of the throttle valve.
18. Install:
• O-ring "1"
• Valve lever housing cover "2"
• Bolt (valve lever housing cover)
"3"
19. Install:
• Carburetor breather hose "1"
Install the carburetor breather hoses
to the carburetor so that the hoses do
not bend near where they are in-
stalled.
ADJUSTING THE ACCELERATOR
PUMP TIMING
Adjustment steps:
In order for the throttle valve height
"a" to achieve the specified value,
tuck under the throttle valve plate "1"
the rod "2" etc. with the same outer di-
ameter as the specified value.
a. Fully turn in the accelerator pump
adjusting screw "3".
b. Check that the link lever "4" has
free play "b" by pushing lightly on
it.
c. Gradually turn out the adjusting
screw while moving the link lever
until it has no more free play.
INSTALLING THE CARBURETOR
1. Install:
• Carburetor joint "1"
• Bracket (cylinder head breather
pipe) "2"
• Bolt (carburetor joint) "3"
• Cylinder head breather pipe "4"
• Cylinder head breather hose 1 "5"
• Cylinder head breather hose 2 "6"
• Cylinder head breather hose 3 "7"2. Install:
• Carburetor "1"
Install the projection "a" between the
carburetor joint slots.
3. Install:
• Hot starter plunger "1"
4. Tighten:
• Bolt (carburetor joint) "1"
• Bolt (air filter joint) "2"
Throttle valve height:
3.1 mm (0.122 in)
Bolt (carburetor joint):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Hot starter plunger:
2 Nm (0.2 m•kg, 1.4
ft•lb)
Bolt (carburetor joint):
3 Nm (0.3 m•kg, 2.2
ft•lb)
Bolt (air filter joint):
3 Nm (0.3 m•kg, 2.2
ft•lb)