2004 YAMAHA TW125 engine

INSTRUMENT AND CONTROL FUNCTIONS
3-7
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34
5
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EAU13560
Fuel cock
The fuel cock supplies fuel from the
tank to the carburetor while filtering it al-
so.
The fuel cock has three positions:
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
This indicates reserve. If you run out of
fuel while riding, move the lever to this
position. Fill the tank at the first oppor-
tunity. Be sure to set the lever back to
“ON” after refueling!

1. Arrow mark positioned over “OFF”
RES
ONFUEL
OFF
1

1. Arrow mark positioned over “ON”
ON
FUEL
RES
OFF
1
ON

1. Arrow mark positioned over “RES”
OFF
ONFUEL RES
1
RES

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INSTRUMENT AND CONTROL FUNCTIONS
3-8
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EAU13600
Starter (choke) knob “”
Starting a cold engine requires a richer
air-fuel mixture, which is supplied by
the starter (choke).
Move the knob in direction (a) to turn on
the starter (choke).
Move the knob in direction (b) to turn off
the starter (choke).
EAU13770
Steering lock
To lock the steering
1. Turn the handlebar all the way to
the right.
2. Open the steering lock cover, and
then insert the steering lock key.
3. Turn the key 1/8 turn counterclock-
wise, push it in while turning the
handlebar slightly to the left, and
then turn the key 1/8 turn clock-
wise.
4. Check that the steering is locked,
remove the key, and then close the
lock cover.
To unlock the steering
1. Open the steering lock cover, and
then insert the steering lock key.
2. Push the key in, turn it 1/8 turn
counterclockwise so that it moves
out, and then release it.
3. Remove the key, and then close
the lock cover.

1. Starter (choke) knob “”
1
(a)
(b)

1. Steering lock cover
2. Steering lock
21

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INSTRUMENT AND CONTROL FUNCTIONS
3-11
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EAU15300
Sidestand
The sidestand is located on the left side
of the frame. Raise the sidestand or
lower it with your foot while holding the
vehicle upright.
NOTE:

The built-in sidestand switch is part of
the ignition circuit cut-off system, which
cuts the ignition in certain situations.
(See further down for an explanation of
the ignition circuit cut-off system.)
WARNING

EWA10240
The vehicle must not be ridden with
the sidestand down, or if the side-
stand cannot be properly moved up
(or does not stay up), otherwise the
sidestand could contact the ground
and distract the operator, resulting
in a possible loss of control.
Yamaha’s ignition circuit cut-off
system has been designed to assist
the operator in fulfilling the respon-
sibility of raising the sidestand be-
fore starting off. Therefore, checkthis system regularly as described
below and have a Yamaha dealer re-
pair it if it does not function proper-
ly.
EAU15311
Ignition circuit cut-off system
The ignition circuit cut-off system (com-
prising the sidestand switch, clutch
switch and neutral switch) has the fol-
lowing functions.

It prevents starting when the trans-
mission is in gear and the side-
stand is up, but the clutch lever is
not pulled.

It prevents starting when the trans-
mission is in gear and the clutch le-
ver is pulled, but the sidestand is
still down.

It cuts the running engine when the
transmission is in gear and the sid-
estand is moved down.
Periodically check the operation of the
ignition circuit cut-off system according
to the following procedure.
WARNING

EWA10250
If a malfunction is noted, have a
Yamaha dealer check the system be-
fore riding.

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INSTRUMENT AND CONTROL FUNCTIONS
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With the engine turned off:
1. Move the sidestand down.
2. Make sure that the engine stop switch is turned on.
3. Turn the key on.
4. Shift the transmission into the neutral position.
5. Push the start switch.
Does the engine start?
With the engine still running:
6. Move the sidestand up.
7. Keep the clutch lever pulled.
8. Shift the transmission into gear.
9. Move the sidestand down.
Does the engine stall?
After the engine has stalled:
10. Move the sidestand up.
11. Keep the clutch lever pulled.
12. Push the start switch.
Does the engine start?
The system is OK. The motorcycle can be ridden.
This check is most reliable if performed with
a warmed-up engine.The neutral switch may be defective.
The motorcycle should not be ridden until
checked by a Yamaha dealer.
The sidestand switch may be defective.
The motorcycle should not be ridden until
checked by a Yamaha dealer.
The clutch switch may be defective.
The motorcycle should not be ridden until
checked by a Yamaha dealer.
YES NO YES NO YES NONOTE:

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PRE-OPERATION CHECKS
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EAU15602
Pre-operation check list
ITEM CHECKS PAGE
Fuel

Check fuel level in fuel tank.

Refuel if necessary.

Check fuel line for leakage.3-6
Engine oil

Check oil level in engine.

If necessary, add recommended oil to specified level.

Check vehicle for oil leakage.6-7
Front brake

Check operation.

If soft or spongy, have Yamaha dealer bleed hydraulic system.

Check lever free play.

Adjust if necessary.

Check brake pads for wear.

Replace if necessary.

Check fluid level in reservoir.

If necessary, add recommended brake fluid to specified level.

Check hydraulic system for leakage.6-17, 6-19, 6-20
Rear brake

Check operation.

Check pedal free play.

Adjust if necessary.6-18, 6-19
Clutch

Check operation.

Lubricate cable if necessary.

Check lever free play.

Adjust if necessary.6-16
Throttle grip

Make sure that operation is smooth.

Check cable free play.

If necessary, have Yamaha dealer adjust cable free play and lubricate cable
and grip housing.6-13, 6-24
Control cables

Make sure that operation is smooth.

Lubricate if necessary.6-23

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5-1
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OPERATION AND IMPORTANT RIDING POINTS
EAU15950
WARNING

EWA10270

Become thoroughly familiar
with all operating controls and
their functions before riding.
Consult a Yamaha dealer re-
garding any control or function
that you do not thoroughly un-
derstand.

Never start the engine or oper-
ate it in a closed area for any
length of time. Exhaust fumes
are poisonous, and inhaling
them can cause loss of con-
sciousness and death within a
short time. Always make sure
that there is adequate ventila-
tion.

Before starting out, make sure
that the sidestand is up. If the
sidestand is not raised com-
pletely, it could contact the
ground and distract the opera-
tor, resulting in a possible loss
of control.
EAU16060
Starting a cold engine
In order for the ignition circuit cut-off
system to enable starting, one of the
following conditions must be met:

The transmission is in the neutral
position.

The transmission is in gear with
the clutch lever pulled and the sid-
estand up.
WARNING

EWA10290

Before starting the engine,
check the function of the igni-
tion circuit cut-off system ac-
cording to the procedure
described on page 3-11.

Never ride with the sidestand
down.
1. Turn the fuel cock lever to “ON”.
2. Turn the key to “ON” and make
sure that the engine stop switch is
set to “”.
3. Shift the transmission into the neu-
tral position.
NOTE:

When the transmission is in the neutral
position, the neutral indicator light
should be on, otherwise have a
Yamaha dealer check the electrical cir-
cuit.
4. Turn the starter (choke) on and
completely close the throttle. (See
page 3-8.)
5. Start the engine by pushing the
start switch.
NOTE:

If the engine fails to start, release the
start switch, wait a few seconds, and
then try again. Each starting attempt
should be as short as possible to pre-
serve the battery. Do not crank the en-
gine more than 10 seconds on any one
attempt.
6. After starting the engine, move the
starter (choke) back halfway.
CAUTION:

ECA11040
For maximum engine life, never ac-
celerate hard when the engine is

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OPERATION AND IMPORTANT RIDING POINTS
5-2
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cold!
7. When the engine is warm, turn the
starter (choke) off.
NOTE:

The engine is warm when it responds
normally to the throttle with the starter
(choke) turned off.
EAU16640
Starting a warm engine
Follow the same procedure as for start-
ing a cold engine with the exception
that the starter (choke) is not required
when the engine is warm.
EAU16671
Shifting
Shifting gears lets you control the
amount of engine power available for
starting off, accelerating, climbing hills,
etc.
The gear positions are shown in the il-
lustration.
NOTE:

To shift the transmission into the neu-
tral position, press the shift pedal down
repeatedly until it reaches the end of its
travel, and then slightly raise it.
1. Shift pedal
2. Neutral position
1
N5
4
3
2
1
2

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OPERATION AND IMPORTANT RIDING POINTS
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CAUTION:

ECA10260

Even with the transmission in
the neutral position, do not
coast for long periods of time
with the engine off, and do not
tow the motorcycle for long dis-
tances. The transmission is
properly lubricated only when
the engine is running. Inade-
quate lubrication may damage
the transmission.

Always use the clutch while
changing gears to avoid damag-
ing the engine, transmission,
and drive train, which are not
designed to withstand the
shock of forced shifting.
EAU32810
Recommended shift points (for
Switzerland only)
The recommended shift points during
acceleration are shown in the table be-
low.
NOTE:

When shifting down two gears at a
time, reduce the speed accordingly
[e.g., down to 35 km/h (22 mi/h) when
shifting from 4th to 2nd gear].
EAU16800
Tips for reducing fuel
consumption
Fuel consumption depends largely on
your riding style. Consider the following
tips to reduce fuel consumption:

Turn the starter (choke) off as
soon as possible.

Shift up swiftly, and avoid high en-
gine speeds during acceleration.

Do not rev the engine while shifting
down, and avoid high engine
speeds with no load on the engine.

Turn the engine off instead of let-
ting it idle for an extended length of
time (e.g., in traffic jams, at traffic
lights or at railroad crossings).
Shift up points:
1st
→
2nd: 23 km/h (14 mi/h)
2nd
→
3rd: 36 km/h (22 mi/h)
3rd
→
4th: 50 km/h (31 mi/h)
4th
→
5th: 60 km/h (37 mi/h)

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