check engine YAMAHA TW125 2002 User Guide

6-8
PERIODIC MAINTENANCE AND MINOR REPAIR
6To install the spark plug
1. Measure the spark plug gap with
a wire thickness gauge and, if
necessary, adjust the gap to
specification.
2. Clean the surface of the spark
plug gasket and its mating sur-
face, and then wipe off any grime
from the spark plug threads.
3. Install the spark plug with the
spark plug wrench, and then
tighten it to the specified torque.
a
a. Spark plug gap
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 specified torque as soon as pos-
sible.4. Install the spark plug cap.
Spark plug gap:
0.6–0.7 mmTightening torque:
Spark plug:
17.5 Nm (1.75 m·kgf)
To check the spark plug
1. Check that the porcelain insula-
tor around the center electrode
of the spark plug is a medium-to-
light tan (the ideal color when the
motorcycle is ridden normally).NOTE:
If the spark plug shows a distinctly
different color, the engine could be
defective. Do not attempt to diagnose
such problems yourself. Instead,
have a Yamaha dealer check the
motorcycle.2. Check the spark plug for elec-
trode erosion and excessive car-
bon or other deposits, and
replace it if necessary.
Specified spark plug:
DR8EA (NGK)
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6-9
PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU04400
Engine oil and oil filter
elementThe engine oil level should be
checked before each ride. In addition,
the oil must be changed and the oil
filter element cleaned at the intervals
specified in the periodic maintenance
and lubrication chart.
To check the engine oil level
1. Place the motorcycle on a level
surface and hold it in an upright
position.NOTE:
Make sure that the motorcycle 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
settles, and then check the oil
level through the check window
located at the bottom-right side
of the crankcase.
NOTE:
The engine oil should be between the
minimum and maximum level marks.4. If the engine oil is below the
minimum level mark, add suffi-
cient oil of the recommended
type to raise it to the correct
level.
2
3 1
1. Engine oil level check window
2. Maximum level mark
3. Minimum level mark
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
engine to collect the used oil.
3. Remove the engine oil filler cap
and drain bolt to drain the oil
from the crankcase.
1
1. Engine oil filler cap
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6-11
PERIODIC MAINTENANCE AND MINOR REPAIR
6 6. Remove the oil filter element and
O-rings.
7. Check the O-ring for damage
and replace it if necessary.
8. Clean the oil filter element with
solvent, and then install it.
NOTE:
Check the oil filter element for dam-
age and replace it if necessary.9. Install the oil filter element cover
by installing the bolts and the
drain bolt, then tightening them
to the specified torques.
1 2
2
1. Oil filter element
2. O-ring (×2)
NOTE:
Make sure that the O-rings are prop-
erly seated.10. Clean the oil strainer with sol-
vent, and then check it for dam-
age and replace it if necessary.
11. Install the oil strainer, compres-
sion 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. Tightening torques:
Oil filter element cover bolt:
10 Nm (1.0 m·kgf)
Oil filter element drain bolt:
10 Nm (1.0 m·kgf)
Tightening torque:
Engine oil drain bolt:
43 Nm (4.3 m·kgf)
Recommended engine oil:
See page 8-1.
Oil quantity:
Without oil filter element
removal:
1.0 L
With oil filter element removal:
1.1 L
Total amount (dry engine):
1.3 L
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6-12
PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU04216
Cleaning the air filter ele-
ment and check hoseThe air filter element should be
cleaned at the intervals specified in
the periodic maintenance and lubrica-
tion chart. Clean the air filter element
more frequently if you are riding in
unusually wet or dusty areas. In addi-
tion, 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
for panel removal and installation
procedures.)2. Remove the air filter case cover
by removing the screws.
1
2
2
1. Air filter case cover
2. Screw (×4)
ECA00105
cC8In order to prevent clutch slip-
page (since the engine oil also
lubricates the clutch), do not
mix any chemical additives
with the oil or use oils of grade
“CD” or higher. In addition, do
not use oils labeled “ENERGY
CONSERVING
II” or higher.
8Make sure that no foreign
material 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, immediately 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.
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6-14
PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU00629
Adjusting the carburetorThe carburetor is an important part of
the engine and requires very sophisti-
cated adjustment. Therefore, most
carburetor adjustments should be left
to a Yamaha dealer, who has the
necessary professional knowledge
and experience. The adjustment
described in the following section,
however, may be serviced by the
owner as part of routine mainte-
nance.
EC000094
cCThe carburetor has been set and
extensively tested at the Yamaha
factory. Changing these settings
without sufficient technical knowl-
edge may result in poor perfor-
mance of or damage to the engine.
EAU01168
Adjusting the engine idling
speedThe engine idling speed must be
checked and, if necessary, adjusted
as follows at the intervals specified in
the periodic maintenance and lubrica-
tion chart.NOTE:
A diagnostic tachometer is needed to
make this adjustment.1. Attach the tachometer to the
spark plug lead.
2. Start the engine and warm it up
for several minutes at 1,000–
2,000 r/min while occasionally
revving it to 4,000–5,000 r/min.NOTE:
The engine is warm when it quickly
responds to the throttle.
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
1. Air filter check hose
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6-15
PERIODIC MAINTENANCE AND MINOR REPAIR
6 3. Check the engine idling speed
and, if necessary, adjust it to
specification by turning the throt-
tle stop screw. To increase the
engine idling speed, turn the
screw in direction a. To
decrease the engine idling
speed, turn the screw in direction
b.
1
a
b
1. Throttle stop screw
NOTE:
If the specified idling speed cannot
be obtained as described above,
have a Yamaha dealer make the
adjustment.
EAU00635
Adjusting the throttle cable
free playThe throttle cable free play should
measure 3–5 mm at the throttle grip.
Periodically check the throttle cable
free play and, if necessary, have a
Yamaha dealer adjust it.
Engine idling speed:
1,450–1,650 r/min
a
a. Throttle cable free play
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6-16
PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU00637
Adjusting the valve
clearanceThe valve clearance changes with
use, resulting in improper air-fuel mix-
ture and/or engine noise. To prevent
this from occurring, the valve clear-
ance must be adjusted by a Yamaha
dealer at the intervals specified in the
periodic maintenance and lubrication
chart.
EAU04401
TiresTo maximize the performance, dura-
bility, and safe operation of your
motorcycle, 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.
EW000082
w8The tire air pressure must be
checked and adjusted on cold
tires (i.e., when the tempera-
ture of the tires equals the
ambient temperature).
8The tire air pressure must be
adjusted in accordance with
the riding speed and with the
total weight of rider, passen-
ger, cargo, and accessories
approved for this model.
Tire air pressure
(measured on cold tires)
Load* Front Rear
Up to 90 kg150 kPa
(1.50 kgf/cm
2,
1.50 bar)150 kPa
(1.50 kgf/cm
2,
1.50 bar)
90 kg–
maximum150 kPa
(1.50 kgf/cm
2,
1.50 bar)175 kPa
(1.75 kgf/cm
2,
1.75 bar)
Maximum load* 180 kg
* Total weight of rider, passenger, cargo and
accessories
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6-26
PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU04369
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 loosen the drive chain, turn
the adjusting plate on each side
of the swingarm in direction b,
and then push the rear wheel for-
ward.
NOTE:
Make sure that both adjusting plates
are in the same position for proper
wheel alignment.
EC000096
cCImproper drive chain slack will
overload 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 6-21 for brake pedal
free play adjustment proce-
dures.)
EW000103
wAfter adjusting the brake pedal
free play, check the operation of
the brake light.
32
a
b
1
1. Brake pedal free play adjusting nut
2. Axle nut
3. Drive chain adjusting plate
Tightening torque:
Axle nut:
90 Nm (9.0 m·kgf)
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6-27
PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU01106
Lubricating the drive chainThe 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.
EC000097
cCThe 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.
2. Spray a drive chain lubricant on
both sides and on the middle of
the chain, making sure that all
side plates and rollers have been
sufficiently oiled.
NOTE:
For a thorough cleaning, have a
Yamaha dealer remove the drive
chain and soak it in solvent.
EAU02962
Checking and lubricating the
cablesThe operation of all control cables
and the condition of the cables
should be checked before each ride,
and the cables and cable ends
should be lubricated if necessary. If a
cable is damaged or does not move
smoothly, have a Yamaha dealer
check or replace it.
Recommended lubricant:
Engine oil
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6-31
PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU00794
Checking the steeringWorn or loose steering bearings may
cause danger. Therefore, the opera-
tion of the steering must be checked
as follows at the intervals specified in
the periodic maintenance and lubrica-
tion chart.
1. Place a stand under the engine
to raise the front wheel off the
ground.
EW000115
wSecurely support the motorcycle
so that there is no danger of it
falling over.
EAU01144
Checking the wheel bearingsThe front and rear wheel bearings
must be checked at the intervals
specified in the periodic maintenance
and lubrication chart. If there is play
in the wheel hub or if the wheel does
not turn smoothly, have a Yamaha
dealer check the wheel bearings.
2. Hold the lower ends of the front
fork legs and try to move them
forward and backward. If any
free play can be felt, have a
Yamaha dealer check or repair
the steering.
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