2004 YAMAHA TW125 check engine light

TABLE OF CONTENTS
SAFETY INFORMATION ............. 1-1
DESCRIPTION ............................. 2-1
Left view ..................................... 2-1
Right view................................... 2-2
Controls and instruments ........... 2-3
INSTRUMENT AND CONTROL
FUNCTIONS ................................. 3-1
Main switch ............................... 3-1
Indicator lights ........................... 3-1
Speedometer unit ...................... 3-2
Handlebar switches ................... 3-3
Clutch lever ............................... 3-4
Shift pedal ................................. 3-4
Brake lever ................................ 3-4
Brake pedal ............................... 3-5
Fuel tank cap ............................. 3-5
Fuel ........................................... 3-6
Fuel cock ................................... 3-7
Starter (choke) knob “ ” .......... 3-8
Steering lock ............................. 3-8
Seat ........................................... 3-9
Helmet holder ............................ 3-9
Shock absorber ....................... 3-10
Carrier ..................................... 3-10
Luggage strap holders ............ 3-10
Sidestand ................................ 3-11Ignition circuit cut-off system ... 3-11
PRE-OPERATION CHECKS ........ 4-1
Pre-operation check list ............ 4-2
OPERATION AND IMPORTANT
RIDING POINTS ........................... 5-1
Starting a cold engine ............... 5-1
Starting a warm engine ............. 5-2
Shifting ...................................... 5-2
Tips for reducing fuel
consumption ............................ 5-3
Engine break-in ......................... 5-4
Parking ...................................... 5-4
PERIODIC MAINTENANCE AND
MINOR REPAIR ............................ 6-1
Owner’s tool kit ......................... 6-1
Periodic maintenance and
lubrication chart ....................... 6-2
Removing and installing
panels ..................................... 6-5
Checking the spark plug ........... 6-6
Engine oil and oil filter
element ................................... 6-7
Cleaning the air filter element
and check hose ..................... 6-10
Adjusting the carburetor .......... 6-12Adjusting the engine idling
speed .................................... 6-12
Adjusting the throttle cable free
play ....................................... 6-13
Adjusting the valve
clearance .............................. 6-13
Tires ........................................ 6-13
Spoke wheels .......................... 6-16
Adjusting the clutch lever free
play ....................................... 6-16
Adjusting the brake lever free
play ....................................... 6-17
Adjusting the brake pedal
position and free play ............ 6-18
Adjusting the rear brake light
switch .................................... 6-19
Checking the front brake pads
and rear brake shoes ............ 6-19
Checking the brake fluid
level ....................................... 6-20
Changing the brake fluid ......... 6-21
Drive chain slack ..................... 6-21
Lubricating the drive chain ...... 6-23
Checking and lubricating the
cables .................................... 6-23
Checking and lubricating the
throttle grip and cable ........... 6-24

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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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5-1
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6
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9

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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PERIODIC MAINTENANCE AND MINOR REPAIR
6-6
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67
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9
To install the panel
Place the panel in the original position.

EAU19602
Checking the spark plug
The spark plug is an important engine
component, which is easy to check.
Since heat and deposits will cause any
spark plug to slowly erode, the spark
plug should be removed and checked
in accordance with the periodic mainte-
nance and lubrication chart. In addition,
the condition of the spark plug can re-
veal the condition of the engine.
To remove the spark plug
1. Remove the spark plug cap.
2. Remove the spark plug as shown,
with the spark plug wrench includ-
ed in the owner’s tool kit.
To check the spark plug
1. Check that the porcelain insulator
around the center electrode of the
spark plug is a medium-to-light tan
(the ideal color when the vehicle is
ridden normally).
NOTE:

If the spark plug shows a distinctly dif-
ferent color, the engine could be defec-
tive. Do not attempt to diagnose such
problems yourself. Instead, have a
Yamaha dealer check the vehicle.
2. Check the spark plug for electrode
erosion and excessive carbon or
other deposits, and replace it if
1. Spark plug cap
1

1. Spark plug wrench
1

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PERIODIC MAINTENANCE AND MINOR REPAIR
6-7
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necessary.
To install the spark plug
1. Measure the spark plug gap with a
wire thickness gauge and, if nec-
essary, adjust the gap to specifica-
tion.
2. Clean the surface of the spark plug
gasket and its mating surface, and
then wipe off any grime from the
spark plug threads.3. Install the spark plug with the
spark plug wrench, and then tight-
en it to the specified torque.
NOTE:

If a torque wrench is not available when
installing a spark plug, a good estimate
of the correct torque is 1/4–1/2 turn
past finger tight. However, the spark
plug should be tightened to the speci-
fied torque as soon as possible.
4. Install the spark plug cap.
EAU19792
Engine oil and oil filter
element
The engine oil level should be checked
before each ride. In addition, the oil
must be changed and the oil filter ele-
ment cleaned at the intervals specified
in the periodic maintenance and lubri-
cation chart.
To check the engine oil level
1. Place the vehicle on a level sur-
face and hold it in an upright posi-
tion.
NOTE:

Make sure that the vehicle is positioned
straight up when checking the oil level.
A slight tilt to the side can result in a
false reading.
2. Start the engine, warm it up for
several minutes, and then turn it
off.
3. Wait a few minutes until the oil set-
tles, and then check the oil level
through the check window located
at the bottom-right side of the Specified spark plug:
NGK/DR8EA
1. Spark plug gap
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)
1

Tightening torque:
Spark plug:
17.5 Nm (1.75 m·kgf,
12.7 ft·lbf)

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PERIODIC MAINTENANCE AND MINOR REPAIR
6-22
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4. If the drive chain slack is incorrect,
adjust it as follows.

EAU22830
To adjust the drive chain slack
1. Loosen the brake pedal free play
adjusting nut.2. Loosen the axle nut.
3. To tighten the drive chain, turn the
adjusting plate on each side of the
swingarm in direction (a). To loos-
en the drive chain, turn the adjust-
ing plate on each side of the
swingarm in direction (b), and then
push the rear wheel forward.
NOTE:

Make sure that both adjusting plates
are in the same position for proper
wheel alignment.
CAUTION:

ECA10570
Improper drive chain slack will over-
load the engine as well as other vital
parts of the motorcycle and can lead
to chain slippage or breakage. To
prevent this from occurring, keep
the drive chain slack within the
specified limits.
4. Tighten the axle nut to the speci-
fied torque.
5. Adjust the brake pedal free play.
(See page 6-18.)
WARNING

EWA10660
After adjusting the brake pedal free
play, check the operation of the
brake light.
1. Drive chain slack
1

1. Brake pedal free play adjusting nut
2. Axle nut
3. Drive chain slack adjusting plate32
1
(a)
(b)
Tightening torque:
Axle nut:
90 Nm (9.0 m·kgf, 65.1 ft·lbf)

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