2004 YAMAHA TW125 ignition

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
3-1
2
34
5
6
7
8
9

EAU10450
Main switch
The main switch controls the ignition
and lighting systems. The various main
switch positions are described below.
EAU10570
ON
All electrical circuits are supplied with
power; the meter lighting, taillight and
auxiliary light come on, and the engine
can be started. The key cannot be re-
moved.
NOTE:

The headlight comes on automatically
when the engine is started and stays on
until the key is turned to “OFF”.
EAU10660
OFF
All electrical systems are off. The key
can be removed.
EAU10980
Indicator lights
EAU11020
Turn signal indicator light “”
This indicator light flashes when the
turn signal switch is pushed to the left or
right.
EAU11060
Neutral indicator light “”
This indicator light comes on when the
transmission is in the neutral position.
EAU11080
High beam indicator light “”
This indicator light comes on when the
high beam of the headlight is switched
OFFON

1. Turn signal indicator light “ ”
2. High beam indicator light “ ”
3. Neutral indicator light “ ”
3
12

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INSTRUMENT AND CONTROL FUNCTIONS
3-11
2
34
5
6
7
8
9

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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PRE-OPERATION CHECKS
4-3
2
3
45
6
7
8
9

Drive chain

Check chain slack.

Adjust if necessary.

Check chain condition.

Lubricate if necessary.6-21, 6-23
Wheels and tires

Check for damage.

Check tire condition and tread depth.

Check air pressure.

Correct if necessary.6-13, 6-16
Brake and shift pedals

Make sure that operation is smooth.

Lubricate pedal pivoting points if necessary.6-24
Brake and clutch levers

Make sure that operation is smooth.

Lubricate lever pivoting points if necessary.6-24
Sidestand

Make sure that operation is smooth.

Lubricate pivot if necessary.6-25
Chassis fasteners

Make sure that all nuts, bolts and screws are properly tightened.

Tighten if necessary.—
Instruments, lights, signals
and switches

Check operation.

Correct if necessary.—
Sidestand switch

Check operation of ignition circuit cut-off system.

If system is defective, have Yamaha dealer check vehicle.3-11
ITEM CHECKS PAGE

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5-1
1
2
3
4
5
6
7
8
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
6-36
2
3
4
5
67
8
9

EAU25850
Troubleshooting
Although Yamaha motorcycles receive
a thorough inspection before shipment
from the factory, trouble may occur dur-
ing operation. Any problem in the fuel,
compression, or ignition systems, for
example, can cause poor starting and
loss of power.
The following troubleshooting chart
represents a quick and easy procedure
for checking these vital systems your-
self. However, should your motorcycle
require any repair, take it to a Yamaha
dealer, whose skilled technicians have
the necessary tools, experience, and
know-how to service the motorcycle
properly.
Use only genuine Yamaha replace-
ment parts. Imitation parts may look like
Yamaha parts, but they are often inferi-
or, have a shorter service life and can
lead to expensive repair bills.

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PERIODIC MAINTENANCE AND MINOR REPAIR
6-37
1
2
3
4
5
6
7
8
9

EAU25901
Troubleshooting chart
WARNING

EWA10840
Keep away open flames and do not smoke while checking or working on the fuel system.
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.
There is no fuel.
Check the compression.
Supply fuel.
The engine does not start.
Check the compression.
Operate the electric starter.2. Compression
There is compression.
There is no compression.
Check the ignition.
Have a Yamaha dealer
check the vehicle.
Remove the spark plug
and check the electrodes.3. Ignition
Wipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug.
Have a Yamaha dealer check the vehicle.
The engine does not start.
Have a Yamaha dealer
check the vehicle.
The engine does not start.
Check the battery.
Operate the electric starter.4. Battery
The engine turns over
quickly.
The engine turns over
slowly.
The battery is good.Check the battery lead connections,
and charge the battery if necessary.
DryWet
Open the throttle halfway and operate
the electric starter.

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SPECIFICATIONS
8-2
1
2
3
4
5
6
7
8
9

4th:
25/27 (0.926)
5th:
23/29 (0.793)
Chassis:
Frame type:
Diamond
Caster angle:
25.8 °
Trail:
93.0 mm (3.66 in)
Front tire:
Type:
With tube
Size:
130/80-18M/C 66P
Manufacturer/model:
BRIDGESTONE/TW-203
Rear tire:
Type:
With tube
Size:
180/80-14M/C 78P
Manufacturer/model:
BRIDGESTONE/TW-204
Loading:
Maximum load:
180 kg (397 lb)
(Total weight of rider, passenger, cargo
and accessories)
Tire air pressure (measured on cold
tires):
Loading condition:
0–90 kg (0–198 lb)
Front:
150 kPa (22 psi) (1.50 kgf/cm
2

)
Rear:
150 kPa (22 psi) (1.50 kgf/cm
2

)
Loading condition:
90–180 kg (198–397 lb)
Front:
150 kPa (22 psi) (1.50 kgf/cm
2

)
Rear:
175 kPa (25 psi) (1.75 kgf/cm
2

)
Front wheel:
Wheel type:
Spoke wheel
Rim size:
18x2.50
Rear wheel:
Wheel type:
Spoke wheel
Rim size:
14M/C x MT4.50
Front brake:
Type:
Single disc brake
Operation:
Right hand operation
Recommended fluid:
DOT 4
Rear brake:
Type:
Drum brake
Operation:
Right foot operation
Front suspension:
Type:
Telescopic fork
Spring/shock absorber type:
Coil spring/oil damper
Wheel travel:
150.0 mm (5.91 in)
Rear suspension:
Type:
Swingarm (monocross)
Spring/shock absorber type:
Coil spring/gas-oil damper
Wheel travel:
150.0 mm (5.91 in)
Electrical system:
Ignition system:
C.D.I.
Charging system:
A.C. magneto
Battery:
Model:
GT6B-3
Voltage, capacity:
12 V, 6.0 Ah
Headlight:
Bulb type:
Halogen bulb

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