check engine YAMAHA TW125 2004 User Guide

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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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crankcase.
NOTE:

The engine oil should be between the
minimum and maximum level marks.
4. If the engine oil is below the mini-
mum level mark, add sufficient oil
of the recommended type to raise
it to the correct level.
To change the engine oil (with or
without oil filter element cleaning)
1. Start the engine, warm it up for
several minutes, and then turn it
off.
2. Place an oil pan under the engineto collect the used oil.
3. Remove the engine oil filler cap
and drain bolt to drain the oil from
the crankcase.
CAUTION:

ECA11000
When removing the engine oil drain
bolt, the O-ring, compression
spring, and oil strainer will fall out.
Take care not to lose these parts.
1. Engine oil level check window
2. Maximum level mark
3. Minimum level mark
2
3 1

1. Engine oil filler cap
1

1. Engine oil drain bolt
1

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11. Install the oil strainer, compression
spring, O-ring and engine oil drain
bolt, and then tighten the drain bolt
to the specified torque.
12. Add the specified amount of the
recommended engine oil, and then
install and tighten the oil filler cap.
CAUTION:

ECA11620

In order to prevent clutch slip-
page (since the engine oil also
lubricates the clutch), do not
mix any chemical additives. Donot use oils with a diesel speci-
fication of “CD” or oils of a high-
er quality than specified. In
addition, do not use oils labeled
“ENERGY CONSERVING II” or
higher.

Make sure that no foreign mate-
rial enters the crankcase.
13. Start the engine, and then let it idle
for several minutes while checking
it for oil leakage. If oil is leaking, im-
mediately turn the engine off and
check for the cause.
14. Turn the engine off, and then
check the oil level and correct it if
necessary.
EAU20830
Cleaning the air filter element
and check hose
The air filter element should be cleaned
at the intervals specified in the periodic
maintenance and lubrication chart.
Clean the air filter element more fre-
quently if you are riding in unusually
wet or dusty areas. In addition, the air
filter check hose must be frequently
checked and cleaned if necessary.
To clean the air filter element
1. Remove panel A. (See page 6-5.)
2. Remove the air filter case cover by
removing the screws.
3. Pull the air filter element out.
Tightening torque:
Engine oil drain bolt:
43 Nm (4.3 m·kgf, 31.1 ft·lbf)
Recommended engine oil:
See page 8-1.
Oil quantity:
Without oil filter element removal:
1.00 L (1.06 US qt)
(0.88 Imp.qt)
With oil filter element removal:
1.10 L (1.16 US qt)
(0.97 Imp.qt)

1. Air filter case cover
2. Screw
1
2
2(×4)

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4. Remove the sponge material from
the air filter element frame, clean it
with solvent, and then squeeze the
remaining solvent out.
5. Apply oil of the recommended type
to the entire surface of the spongematerial, and then squeeze the ex-
cess oil out.
NOTE:

The sponge material should be wet but
not dripping.
6. Pull the sponge material over the
air filter element frame.
7. Insert the element into the air filter
case.
CAUTION:

ECA10480

Make sure that the air filter ele-
ment is properly seated in the
air filter case.

The engine should never be op-
erated without the air filter ele-
ment installed, otherwise the
piston(s) and/or cylinder(s) may
become excessively worn.
8. Install the air filter case cover by in-
stalling the screws.
9. Install the panel.
To clean the air filter check hose
1. Check the hose at the bottom of
the air filter case for accumulated
dirt or water.
2. If dirt or water is visible, remove
the hose, clean it, and then install
it.

1. Sponge material
2. Air filter element frame
1
2

Recommended oil:
Engine oil
1. Air filter check hose
1

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EAU21280
Adjusting the carburetor
The carburetor is an important part of
the engine and requires very sophisti-
cated adjustment. Therefore, most car-
buretor adjustments should be left to a
Yamaha dealer, who has the neces-
sary professional knowledge and expe-
rience. The adjustment described in the
following section, however, may be ser-
viced by the owner as part of routine
maintenance.
CAUTION:

ECA10550
The carburetor has been set and ex-
tensively tested at the Yamaha fac-
tory. Changing these settings
without sufficient technical knowl-
edge may result in poor perfor-
mance of or damage to the engine.
EAU21340
Adjusting the engine idling
speed
The engine idling speed must be
checked and, if necessary, adjusted as
follows at the intervals specified in the
periodic maintenance and lubrication
chart.
The engine should be warm before
making this adjustment.
NOTE:


The engine is warm when it quickly
responds to the throttle.

A diagnostic tachometer is needed
to make this adjustment.
1. Attach the tachometer to the spark
plug lead.
2. Check the engine idling speed
and, if necessary, adjust it to spec-
ification by turning the throttle stop
screw. To increase the engine
idling speed, turn the screw in di-
rection (a). To decrease the en-
gine idling speed, turn the screw in
direction (b).
NOTE:

If the specified idling speed cannot be
obtained as described above, have a
Yamaha dealer make the adjustment.
1. Throttle stop screw
Engine idling speed:
1450–1650 r/min
1
(a) (b)

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EAU21380
Adjusting the throttle cable
free play
The throttle cable free play should mea-
sure 3.0–5.0 mm (0.12–0.20 in) at the
throttle grip. Periodically check the
throttle cable free play and, if neces-
sary, have a Yamaha dealer adjust it.
EAU21400
Adjusting the valve clearance
The valve clearance changes with use,
resulting in improper air-fuel mixture
and/or engine noise. To prevent this
from occurring, the valve clearance
must be adjusted by a Yamaha dealer
at the intervals specified in the periodic
maintenance and lubrication chart.
EAU21581
Tires
To maximize the performance, durabil-
ity, and safe operation of your motorcy-
cle, note the following points regarding
the specified tires.
Tire air pressure
The tire air pressure should be checked
and, if necessary, adjusted before each
ride.
WARNING

EWA10500

The tire air pressure must be
checked and adjusted on cold
tires (i.e., when the temperature
of the tires equals the ambient
temperature).

The tire air pressure must be ad-
justed in accordance with the
riding speed and with the total
weight of rider, passenger, car-
go, and accessories approved
for this model.
1. Throttle cable free play
1

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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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EAU23011
Lubricating the drive chain
The drive chain must be cleaned and
lubricated at the intervals specified in
the periodic maintenance and lubrica-
tion chart, otherwise it will quickly wear
out, especially when riding in dusty or
wet areas. Service the drive chain as
follows.
CAUTION:

ECA10580
The drive chain must be lubricated
after washing the motorcycle or
riding in the rain.
1. Remove all dirt and mud from the
drive chain with a brush or cloth.
NOTE:

For a thorough cleaning, have a
Yamaha dealer remove the drive chain
and soak it in solvent.
2. Spray Yamaha Chain and Cable
Lube or a high-quality spray-type
drive chain lubricant on both sides
and on the middle of the chain,
making sure that all side plates
and rollers have been sufficientlyoiled.
EAU23100
Checking and lubricating the
cables
The operation of all control cables and
the condition of the cables should be
checked before each ride, and the ca-
bles and cable ends should be lubricat-
ed if necessary. If a cable is damaged
or does not move smoothly, have a
Yamaha dealer check or replace it.
WARNING

EWA10720
Damage to the outer sheath may in-
terfere with proper cable operation
and will cause the inner cable to
rust. Replace a damaged cable as
soon as possible to prevent unsafe
conditions.
Recommended lubricant:
Engine oil

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CAUTION:

ECA10590
If any damage is found or the front
fork does not operate smoothly,
have a Yamaha dealer check or re-
pair it.
EAU23280
Checking the steering
Worn or loose steering bearings may
cause danger. Therefore, the operation
of the steering must be checked as fol-
lows at the intervals specified in the pe-
riodic maintenance and lubrication
chart.
1. Place a stand under the engine to
raise the front wheel off the
ground.
WARNING

EWA10750
Securely support the vehicle so that
there is no danger of it falling over.
2. Hold the lower ends of the front
fork legs and try to move them for-
ward and backward. If any free
play can be felt, have a Yamaha
dealer check or repair the steering.

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CAUTION:

ECA11190
Do not overtighten the screw, other-
wise the lens may break.
EAU24350
Supporting the motorcycle
Since this model is not equipped with a
centerstand, follow these precautions
when removing the front and rear
wheel or performing other maintenance
requiring the motorcycle to stand up-
right. Check that the motorcycle is in a
stable and level position before starting
any maintenance. A strong wooden
box can be placed under the engine for
added stability.
To service the front wheel
1. Stabilize the rear of the motorcycle
by using a motorcycle stand or, if
an additional motorcycle stand is
not available, by placing a jack un-
der the frame in front of the rear
wheel.
2. Raise the front wheel off the
ground by using a motorcycle
stand.
To service the rear wheel
Raise the rear wheel off the ground by
using a motorcycle stand or, if a motor-
cycle stand is not available, by placing
a jack either under each side of theframe in front of the rear wheel or under
each side of the swingarm.

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