2008 YAMAHA WR 450F stop start

1-1
DESCRIPTION
GENERAL INFORMATION
DESCRIPTION
• The machine you have purchased may differ slightly from those shown in the following.
• Designs and specifications are subject to change without notice.
1. Clutch lever
2. Hot starter lever
3. Engine stop switch
4. Multi-function display
5. Main switch
6. Start switch
7. Front brake lever
8. Throttle grip
9. Radiator cap
10. Fuel tank cap
11. Taillight
12. Kickstarter crank
13. Fuel tank14. Headlight
15. Radiator
16. Coolant drain bolt
17. Rear brake pedal
18. Valve joint
19. Fuel cock
20. Cold starter knob
21. Air cleaner
22. Catch tank
23. Drive chain
24. Shift pedal
25. Oil dipstick
26. Front fork
1

1-8
CONTROL FUNCTIONS
CONTROL FUNCTIONS
MAIN SWITCH
Functions of the respective switch po-
sitions are as follows:
ON:
The engine can be started only at this
position.
OFF:
All electrical circuits are switched off.
Main switch indicator light
The main switch "1" is equipped with
an indicator light "2" to avoid forget-
ting to turn it off. This light functions
as follows.
• It lights up with the main switch
"ON".
• It goes out when the engine in-
creases its speed after being start-
ed.
• It lights up again when the engine is
stopped.
If the indicator light will not light up
with the main switch "ON", it shows a
lack of the battery voltage. Recharge
the battery.
ENGINE STOP SWITCH
The engine stop switch "1" is located
on the left handlebar. Continue push-
ing the engine stop switch till the en-
gine comes to a stop.
START SWITCH
The start switch "1" is located on the
right handlebar. Push this switch to
crank the engine with the starter.CLUTCH LEVER
The clutch lever "1" is located on the
left handlebar; it disengages or en-
gages the clutch. Pull the clutch lever
to the handlebar to disengage the
clutch, and release the lever to en-
gage the clutch. The lever should be
pulled rapidly and released slowly for
smooth starts.
SHIFT PEDAL
The gear ratios of the constant-mesh
5 speed transmission are ideally
spaced. The gears can be shifted by
using the shift pedal "1" on the left
side of the engine.
KICKSTARTER CRANK
Rotate the kickstarter crank "1" away
from the engine. Push the starter
down lightly with your foot until the
gears engage, then kick smoothly
and forcefully to start the engine. This
model has a primary kickstarter crank
so the engine can be started in any
gear if the clutch is disengaged. In
normal practices, however, shift to
neutral before starting.
THROTTLE GRIP
The throttle grip "1" is located on the
right handlebar; it accelerates or de-
celerates the engine. For accelera-
tion, turn the grip toward you; for
deceleration, turn it away from you.FRONT BRAKE LEVER
The front brake lever "1" is located on
the right handlebar. Pull it toward the
handlebar to activate the front brake.
REAR BRAKE PEDAL
The rear brake pedal "1" is located on
the right side of the machine. Press
down on the brake pedal to activate
the rear brake.
FUEL COCK
The fuel cock supplies fuel from the
tank to carburetor and also filters the
fuel. The fuel cock has the three posi-
tions:
OFF:
With the lever in this position, fuel will
not flow. Always return the lever to
this position when the engine is not
running.
ON:
With the lever in this position, fuel
flows to the carburetor. Normal riding
is done with the lever in this position.
RES:
With the lever in this position fuel
flows to the carburetor from the re-
serve section of the fuel tank after the
main supply of the fuel has been de-
pleted. Normal riding is possible with
the lever is in this position, but it is
recommended to add fuel as soon as
possible.

1-9
MULTI-FUNCTION DISPLAY
COLD STARTER KNOB
When cold, the engine requires a
richer air-fuel mixture for starting. A
separate starter circuit, which is con-
trolled by the cold starter knob "1",
supplies this mixture. Pull the cold
starter knob out to open the circuit for
starting. When the engine has
warmed up, push it in to close the cir-
cuit.
HOT STARTER LEVER
The hot starter lever "1" is used when
starting a warm engine. Use the hot
starter lever when starting the engine
again immediately after it was
stopped (the engine is still warm).
Pulling the hot starter lever injects
secondary air to thin the air-fuel mix-
ture temporarily, allowing the engine
to be started more easily.
SIDESTAND
This sidestand "1" is used to support
only the machine when standing or
transporting it.
• Never apply additional force to
the sidestand.
• Hold up the sidestand before
starting out.
MULTI-FUNCTION DISPLAY
Be sure to stop the machine before
making any setting changes to the
multi-function display.
The multi-function display is
equipped with the following:
BASIC MODE:
• Speedometer
•Clock
• Two tripmeters (which shows the
distance that has been traveled
since it was last set to zero)
RACE MODE:
• Timer (which shows the time that
has been accumulated since the
start of timer measurement)
• Tripmeter (which shows the accu-
mulated travel distance in timer
measurement)
• Change tripmeter digits (capable of
change to any given ones)
DESCRIPTION
Operation buttons:
1. Select button "SLCT 1"
2. Select button "SLCT 2"
3. Reset button "RST"
Screen display:
4. Tripmeter indicator
5. Tripmeter indicator
6. Timer indicator
7. Clock/Timer
8. Speedometer
9. Odometer/Tripmeter
The operation buttons can be pushed
in the following two manners:
Short push: Push the button. ( )
Long push: Push the button for 2 sec-
onds or more. ( )
BASIC MODE
Changing speedometer display
(for U.K.)
1. Push the "SLCT2" button for 2
seconds or more to change the
speedometer units. The speed-
ometer display will change in the
following order:
MPH→km/h→MPH.Setting the time
1. Push the "SLCT1" button for 2
seconds or more to enter the time
setting mode.
2. Push the "RST" button to change
the display for time indication.
The display will change in the fol-
lowing order:
Hour→Minute→Second→Hour.
The digits capable of setting go on
flashing.
3. Push the "SLCT1" button (plus) or
"SLCT2" button (minus) and
change the time. A long push on
the button will fast-forward the
time.
4. To end the setting, push the
"RST" button for 2 seconds or
more.
• In a 30-second absence of button
operation, the setting will come to
an end with the indicated time.
• To reset the seconds, push the
"SLCT1" button or "SLCT2" button.
Changing odometer and tripmeter
A/B (TRIP A/B)
1. Push the "SLCT2" button to
change the tripmeter display. The
display will change in the follow-
ing order:
Odometer →TRIP A→TRIP B→
TRIP A→Odometer.

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MULTI-FUNCTION DISPLAY
To reset the digits, select the tripme-
ter involved and push the "RST" but-
ton for 2 seconds or more.
CHANGEOVER TO BASIC MODE/
RACE MODE
• Measurement using the timer func-
tion can be made in RACE MODE.
• Indicator will light up as an
identifier that shows RACE MODE
has been selected.
• RACE MODE cannot display the
functions as in BASIC MODE.
• Changeover to RACE MODE forc-
es the digits for tripmeter A (TRIP
A) in BASIC MODE to be reset.
Changeover from BASIC MODE to
RACE MODE
1. Push the "SLCT1" button and
"SLCT2" button for 2 seconds or
more at the same time to change
over to RACE MODE.
Changeover to RACE MODE will put
manual start measurement on stand-
by causing and to flash. (For
manual start, refer to "Putting mea-
surement on standby" in "RACE
MODE".)
Returning to BASIC MODE from
RACE MODE
It is possible to return to BASIC
MODE with timer measurement at a
stop.
1. Check that the timer is not in op-
eration. If the timer is in operation,
stop the timer by pushing the
"SLCT1" button and "SLCT2" but-
ton at the same time.
2. Push the "SLCT1" button and
"SLCT2" button for 2 seconds or
more at the same time to change
over to BASIC MODE.
RACE MODE
Putting measurement on standby
Starting measurement consists of the
following two starts, either of which
can be selected.
• Manual start
Starting measurement by the rider
himself operating the button. (A long
push on the "SLCT2" button will put
measurement on standby.)
• Auto start
Starting timer measurement automat-
ically on detection of the movement of
the machine. (A long push on the
"SLCT1" button will put measurement
on standby.)
Manual start
Initial setting at changeover to RACE
MODE will remain for manual start.
1. Check that changeover to RACE
MODE has been made. (Refer to
"Changeover from BASIC MODE
to RACE MODE".)
When the machine is made ready for
a run by manual start, and will
start flashing.
2. Start timer measurement by
pushing the "RST" button.
3. When stopping timer measure-
ment, pushing the "SLCT1" but-
ton and "SLCT2" button at the
same time.
If the machine is run while timer mea-
surement is not made, no change will
occur to the digit in tripmeter A (TRIP
A).
4. To resume the measurement,
again push the "SLCT1" button
and "SLCT2" button at the same
time.
Auto start
1. Check that changeover has been
made to RACE MODE. (Refer to
"Changeover from BASIC MODE
to RACE MODE".)
2. Make the machine ready for a run
by pushing the "SLCT1" button for
2 seconds or more.
When the measurement is made
ready for a run by auto start, and
will start flashing. Timer display
will turn on scrolling from left to right.
3. Run the machine and start timer
measurement.
4. To stop timer measurement,
pushing the "SLCT1" button and
"SLCT2" button at the same time.

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MULTI-FUNCTION DISPLAY
If the machine is run while timer mea-
surement is not made, no change will
occur to the digit in tripmeter A (TRIP
A).
5. To resume the measurement,
again pushing the "SLCT1" button
and "SLCT2" button at the same
time.
Resetting measurement data
Resetting can be made in the follow-
ing two manners.
Resetting is possible while timer
measurement is made:
• Reset tripmeter A.
Resetting is possible while timer
measurement is not made:
• Reset tripmeter A and timer.
Resetting tripmeter A (TRIP A)
1. Check that the timer is in opera-
tion. If the timer is not in opera-
tion, start the timer by pushing the
"SLCT1" button and "SLCT2" but-
ton at the same time.
2. Reset tripmeter A (TRIP A) dis-
play by pushing the "RST" button
for 2 seconds or more.
If reset, and travel distance dis-
play will go on flashing for four sec-
onds.
Resetting tripmeter A (TRIP A) and
timer
1. Check that the timer is not in op-
eration. If the timer is in operation,
stop it by pushing the "SLCT1"
button and "SLCT2" button at the
same time.
2. Reset all measured data by push-
ing the "RST" button for 2 sec-
onds or more.
• Resetting will reset the timer display
and travel distance display and put
measurement on standby.
• Auto start attempt will put measure-
ment on standby as such. Likewise,
manual start attempt will put mea-
surement on standby as such.
Correcting tripmeter A (TRIP A)
1. Change the travel distance dis-
play by pushing the "SLCT1" but-
ton (plus) or "SLCT2" button
(minus). A long push on the but-
ton will fast-forward the change.
Change can be made any time while
timer measurement is or is not being
made.

1-14
STARTING AND BREAK-IN
STARTING AND BREAK-IN
FUEL
Always use the recommended fuel as
stated below. Also, be sure to use
new gasoline the day of a race.
Use only unleaded gasoline. The
use of leaded gasoline will cause
severe damage to the engine inter-
nal parts such as valves, piston
rings, and exhaust system, etc.
If knocking or pinging occurs, use a
different brand of gasoline or higher
octane grade.
• For refueling, be sure to stop the
engine and use enough care not
to spill any fuel. Also be sure to
avoid refueling close to a fire.
• Refuel after the engine, exhaust
pipe, etc. have cooled off.
HANDLING NOTE
Never start or run the engine in a
closed area. The exhaust fumes
are poisonous; they can cause
loss of consciousness and death
in a very short time. Always oper-
ate the machine in a well-ventilated
area.
• The carburetor on this machine
has a built-in accelerator pump.
Therefore, when starting the en-
gine, do not operate the throttle
or the spark plug will foul.
• Unlike a two-stroke engine, this
engine cannot be kick started
when the throttle is open be-
cause the kickstarter may kick
back. Also, if the throttle is open
the air/fuel mixture may be too
lean for the engine to start.
• Before starting the machine, per-
form the checks in the pre-opera-
tion check list.
AIR FILTER MAINTENANCE
According to "CLEANING THE AIR
FILTER ELEMENT" section in the
CHAPTER 3, apply the foam-air-filter
oil or its equivalent to the element.
(Excess oil in the element may ad-
versely affect engine starting.)
STARTING A COLD ENGINE
This model is equipped with an igni-
tion circuit cut-off system. The engine
can be started under the following
conditions.
• When the transmission is in neutral.
• When the clutch is disengaged with
the transmission in any position.
However, it is recommended to shift
into neutral before starting the en-
gine.
1. Inspect the coolant level.
2. Turn the fuel cock to "ON".
3. Push on the main switch to "ON".
4. Shift the transmission into neutral.
5. Fully open the cold starter knob
"1".
6. Start the engine by pushing the
start switch or by kicking the kick-
starter crank.
If the engine fails to start by pushing
the start switch, release the switch,
wait a few seconds, and then try
again. Each starting attempt should
be as short as possible to preserve
the battery. Do not crank the engine
more than 10 seconds on any one at-
tempt. If the engine does not start
with the starter motor, try using the
kickstarter crank.
• If the starter motor will not turn
when pushing the start switch,
stop pushing it immediately and
kick start the engine in order to
avoid the load on the motor.
• Do not open the throttle while
kicking the kickstarter crank.
Otherwise, the kickstarter crank
may kick back.
7. Return the cold starter knob to its
original position and run the en-
gine at 3,000–5,000 r/min for 1 or
2 minutes.
Since this model is equipped with an
accelerator pump, if the engine is
raced (the throttle opened and
closed), the air/fuel mixture will be too
rich and the engine may stall. Also
unlike a two-stroke engine, this model
can idle.
Do not warm up the engine for ex-
tended periods of time.
STARTING A WARM ENGINE
Do not operate the cold starter knob
and throttle. Pull the hot starter lever
"1" and start the engine by pushing
the start switch or by kicking the kick-
starter crank forcefully with a firm
stroke. As soon as the engine starts,
Release the hot starter lever to close
the air passage.
Restarting an engine after a fall
Pull the hot starter lever and start the
engine. As soon as the engine starts,
Release the hot starter lever to close
the air passage. Recommended fuel:
Premium unleaded
gasoline only with a re-
search octane number
of 95 or higher.

1-15
STARTING AND BREAK-IN
The engine fails to start
Pull the hot starter lever all the way
out and while holding the lever, kick
the kickstarter crank 10 to 20 times to
clear the engine. Then, restart the en-
gine. Refer to "Restarting an engine
after a fall".
Observe the following break-in
procedures during initial operation
to ensure optimum performance
and avoid engine damage.
BREAK-IN PROCEDURES
1. Before starting the engine, fill the
fuel tank with the fuel.
2. Perform the pre-operation checks
on the machine.
3. Start and warm up the engine.
Check the idle speed, and check
the operation of the controls and
the engine stop switch. Then, re-
start the engine and check its op-
eration within no more than 5
minutes after it is restarted.4. Operate the machine in the lower
gears at moderate throttle open-
ings for five to eight minutes.
5. Check how the engine runs when
the machine is ridden with the
throttle 1/4 to 1/2 open (low to me-
dium speed) for about one hour.
6. Restart the engine and check the
operation of the machine through-
out its entire operating range. Re-
start the machine and operate it
for about 10 to 15 more minutes.
The machine will now be ready to
race.
• After the break-in or before each
race, you must check the entire
machine for loose fittings and
fasteners as per "TORQUE-
CHECK POINTS". Tighten all
such fasteners as required.
• When any of the following parts
have been replaced, they must
be broken in.
CYLINDER AND CRANKSHAFT:
About one hour of break-in oper-
ation is necessary.
PISTON, RING, VALVES, CAM-
SHAFTS AND GEARS:
These parts require about 30
minutes of break-in operation at
half-throttle or less. Observe the
condition of the engine carefully
during operation.
Thro
ttle
grip
op-
era-
tion*Cold
start-
er
knobHot
start-
er le-
ver
St
ar
ti
n
g
a
c
ol
d
e
n
gi
n
eAir tempera-
ture = less
than 5 °C (41
°F)Ope
n 3
or 4
time
sON OFF
Air tempera-
ture = more
than 5 °C (41
°F)Non
eON OFF
Air tempera-
ture (normal
temperature)
= between 5
°C (41 °F)
and 25 °C
(77 °F)Non
eON/
OFFOFF
Air tempera-
ture = more
than 25 °C
(77 °F)Non
eOFF OFF
Starting an en-
gine after a long
period of timeNon
eON OFF
Restarting a
warm engineNon
eOFF ON
Restarting an en-
gine after a fallNon
eOFF ON
* Operate the throttle grip before kick
starting.

1-17
CLEANING AND STORAGE
CLEANING AND STORAGE
CLEANING
Frequent cleaning of your machine
will enhance its appearance, maintain
good overall performance, and ex-
tend the life of many components.
1. Before washing the machine,
block off the end of the exhaust
pipe to prevent water from enter-
ing. A plastic bag secured with a
rubber band may be used for this
purpose.
2. If the engine is excessively
greasy, apply some degreaser to
it with a paint brush. Do not apply
degreaser to the chain, sprockets,
or wheel axles.
3. Rinse the dirt and degreaser off
with a garden hose; use only
enough pressure to do the job.
Excessive hose pressure may
cause water seepage and contami-
nation of wheel bearings, front
forks, brakes and transmission
seals. Many expensive repair bills
have resulted from improper high
pressure detergent applications
such as those available in coin-op-
erated car washers.
4. After the majority of the dirt has
been hosed off, wash all surfaces
with warm water and a mild deter-
gent. Use an old toothbrush to
clean hard-to-reach places.
5. Rinse the machine off immediate-
ly with clean water, and dry all
surfaces with a soft towel or cloth.
6. Immediately after washing, re-
move excess water from the
chain with a paper towel and lubri-
cate the chain to prevent rust.
7. Clean the seat with a vinyl uphol-
stery cleaner to keep the cover
pliable and glossy.
8. Automotive wax may be applied
to all painted or chromed surfac-
es. Avoid combination cleaner-
waxes, as they may contain abra-
sives.
9. After completing the above, start
the engine and allow it to idle for
several minutes.STORAGE
If your machine is to be stored for 60
days or more, some preventive mea-
sures must be taken to avoid deterio-
ration. After cleaning the machine
thoroughly, prepare it for storage as
follows:
1. Drain the fuel tank, fuel lines, and
the carburetor float bowl.
2. Remove the spark plug, pour a ta-
blespoon of SAE 10W-30 motor
oil in the spark plug hole, and re-
install the plug. With the engine
stop switch pushed in, kick the en-
gine over several times to coat the
cylinder walls with oil.
3. Remove the drive chain, clean it
thoroughly with solvent, and lubri-
cate it. Reinstall the chain or store
it in a plastic bag tied to the frame.
4. Lubricate all control cables.
5. Block the frame up to raise the
wheels off the ground.
6. Tie a plastic bag over the exhaust
pipe outlet to prevent moisture
from entering.
7. If the machine is to be stored in a
humid or salt-air environment,
coat all exposed metal surfaces
with a film of light oil. Do not apply
oil to rubber parts or the seat cov-
er.
Make any necessary repairs before
the machine is stored.