2004 YAMAHA TW125 check engine

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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DESCRIPTION
2-2
2
3
4
5
6
7
8
9

EAU10420
Right view
1
2
65 3
4
7
1. Carrier
2. Battery (page 6-27)
3. Engine oil filter element (page 6-7)
4. Engine oil level check window (page 6-7)
5. Brake pedal (page 3-5)
6. Owner’s tool kit (page 6-1)
7. Fuse (page 6-28)

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INSTRUMENT AND CONTROL FUNCTIONS
3-8
1
2
3
4
5
6
7
8
9

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
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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INSTRUMENT AND CONTROL FUNCTIONS
3-12
1
2
3
4
5
6
7
8
9
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
4-2
1
2
3
4
5
6
7
8
9

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
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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OPERATION AND IMPORTANT RIDING POINTS
5-4
2
3
4
56
7
8
9

EAU16830
Engine break-in
There is never a more important period
in the life of your engine than the period
between 0 and 1000 km (600 mi). For
this reason, you should read the follow-
ing material carefully.
Since the engine is brand new, do not
put an excessive load on it for the first
1000 km (600 mi). The various parts in
the engine wear and polish themselves
to the correct operating clearances.
During this period, prolonged full-throt-
tle operation or any condition that might
result in engine overheating must be
avoided.
EAU16990
0–500 km (0–300 mi)
Avoid prolonged operation above 1/3
throttle.
500–1000 km (300–600 mi)
Avoid prolonged operation above 1/2
throttle.
CAUTION:

ECA11500
After 1000 km (600 mi) of operation,the engine oil must be changed, and
the oil filter element and the oil
strainer cleaned.
1000 km (600 mi) and beyond
The vehicle can now be operated nor-
mally.
CAUTION:

ECA10270
If any engine trouble should occur
during the engine break-in period,
immediately have a Yamaha dealer
check the vehicle.
EAU17170
Parking
When parking, stop the engine, remove
the key from the main switch, and then
turn the fuel cock lever to “OFF”.
WARNING

EWA10310

Since the engine and exhaust
system can become very hot,
park in a place where pedestri-
ans or children are not likely to
touch them.

Do not park on a slope or on soft
ground, otherwise the vehicle
may overturn.

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