engine YAMAHA DT125R 2002 Owner's Guide

6-17
PERIODIC MAINTENANCE AND MINOR REPAIR
67. Pull the sponge material over the
frame.
8. Install the air filter element onto
the guide, and then tighten the
wing nut.
9. Insert the air filter element into
the case.
10. Install the air filter case cover by
installing the screws.
11. Install the panel.
EC000082
cC8Make sure that the air filter ele-
ment is properly seated in the
air filter case.
8The engine should never be
operated without the air filter
element installed, otherwise
the piston and/or cylinder may
become excessively worn.
EAU00632
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.
1. 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.2. Check the engine idling speed
and, if necessary, adjust it to
specification by turning the throt-
tle stop screw.
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.
Recommended oil:
2-stroke engine oil
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6-18
PERIODIC MAINTENANCE AND MINOR REPAIR
6
b
a
1
1. Throttle 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.
NOTE:
If the specified idling speed cannot
be obtained as described above,
have a Yamaha dealer make the
adjustment.
EAU00634
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, adjust it
as follows.NOTE:
The engine idling speed must be cor-
rectly adjusted before checking and
adjusting the throttle cable free play.
a
a. Free play
Engine idling speed:
1,250–1,450 r/min
1. Loosen the locknut.
2. To increase the throttle cable
free play, turn the adjusting nut
in direction a. To decrease the
throttle cable free play, turn the
adjusting nut in direction b.
3. Tighten the locknut.
2
1
b
a
1. Locknut
2. Adjusting nut
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6-28
PERIODIC MAINTENANCE AND MINOR REPAIR
6
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.3. Tighten the axle nut to the speci-
fied torque.2. Wipe the drive chain dry.
3. Thoroughly lubricate the drive
chain with a special O-ring chain
lubricant.
ECA00052
cCDo not use engine oil or any other
lubricants for the drive chain, as
they may contain substances that
could damage the O-rings.
EAU03006
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. Clean the drive chain with
kerosene and a small soft brush.
ECA00053
cCTo prevent damaging the O-rings,
do not clean the drive chain with
steam cleaners, high-pressure
washers or inappropriate solvents.
Tightening torque:
Axle nut:
90 Nm (9.0 m0kgf)
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6-29
PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU04034
Checking and lubricating the
throttle grip and cableThe operation of the throttle grip
should be checked before each ride.
In addition, the cable should be lubri-
cated or replaced at the intervals
specified in the periodic maintenance
chart.
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.
EW000112
wDamage to the outer sheath may
interfere with proper cable opera-
tion 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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6-30
PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU00774
Adjusting the Autolube
pumpThe Autolube pump is a vital and
sophisticated component of the
engine, which must be adjusted by a
Yamaha dealer at the intervals speci-
fied in the periodic maintenance and
lubrication chart.
EAU03370
Checking and lubricating the
brake and shift pedalsThe operation of the brake and shift
pedals should be checked before
each ride, and the pedal pivots
should be lubricated if necessary.
EAU03164
Checking and lubricating the
brake and clutch leversThe operation of the brake and clutch
levers should be checked before
each ride, and the lever pivots should
be lubricated if necessary.
Recommended lubricant:
Lithium-soap-based grease
(all-purpose grease)
Recommended lubricant:
Lithium-soap-based grease
(all-purpose grease)
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6-32
PERIODIC MAINTENANCE AND MINOR REPAIR
6 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.
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.
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.
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6-39
PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU00898
Front wheelTo remove the front wheel
EW000122
w8It is advisable to have a
Yamaha dealer service the
wheel.
8Securely support the motorcy-
cle so that there is no danger
of it falling over.1. Remove the brake disc cover by
removing the screws.
122
1. Disc cover
2. Screw (×2)
To service the rear wheel
Raise the rear wheel off the ground
by using a motorcycle stand or, if a
motorcycle stand is not available, by
placing a jack either under each side
of the frame in front of the rear wheel
or under each side of the swingarm.
EAU01579
Supporting the motorcycleSince this model is not equipped with
a centerstand, follow these precau-
tions when removing the front and
rear wheel or performing other main-
tenance requiring the motorcycle to
stand upright. Check that the motor-
cycle 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 motorcy-
cle by using a motorcycle stand
or, if an additional motorcycle
stand is not available, by placing
a jack under the frame in front of
the rear wheel.
2. Raise the front wheel off the
ground by using a motorcycle
stand.
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PERIODIC MAINTENANCE AND MINOR REPAIR
6
Check if there is fuel1. Fuel
Enough fuel.
No fuel.
Go to compression check.
Supply fuel.
Engine doesn’t start, go to compression check.
Use kickstarter.2. Compression
There is compression.
No compression.
Go to ignition check.
Ask a Yamaha dealer to
Remove spark plug3. Ignition
Wet.
Dry.
Wipe clean with dry cloth and correct
Ask a Yamaha dealer to inspect.
Engine doesn’t start, ask a YamahaOpen throttle half-way and start
in the fuel tank.
and check electrodes.spark gap or replace spark plug. the engine.
dealer to inspect. inspect.
EAU03108
Troubleshooting charts
EW000125
wKeep away open flames and do not smoke while checking or working on the fuel system.
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PERIODIC MAINTENANCE AND MINOR REPAIR
6
Wait until the
Check the coolant level in the
Level is OK.Level is low, check the
NoLeakage.
Ask a Yamaha dealer to inspectAdd coolant. (See NOTE.)
Restart the engine. If the engine overheats again, ask a
engine has cooled.reservoir tank and/or radiator.cooling system for leakage.
Yamaha dealer to inspect and repair the cooling system.leakage.
and repair the cooling system.
4. Engine overheating
EW000070
w8Do not remove the radiator cap when the engine and radiator are hot. Scalding hot fluid and steam may be
blown out under pressure, which could cause serious injury. Be sure to wait until the engine has cooled.
8After removing the radiator cap retaining bolt, place a thick rag, like a towel, over the radiator cap, and then
slowly rotate the cap counterclockwise to the detent to allow any residual pressure to escape. When the
hissing sound has stopped, press down on the cap while turning it counterclockwise, and then remove the
cap.NOTE:
If it is difficult to get the recommended coolant, tap water can be temporarily used, provided that it is changed to the rec-
ommended coolant as soon as possible.
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7-1
EAU03521
MOTORCYCLE CARE AND STORAGE
7
CareWhile the open design of a motorcy-
cle reveals the attractiveness of the
technology, it also makes it more vul-
nerable. Rust and corrosion can
develop even if high-quality compo-
nents are used. A rusty exhaust pipe
may go unnoticed on a car, however,
it detracts from the overall appear-
ance of a motorcycle. Frequent and
proper care does not only comply
with the terms of the warranty, but it
will also keep your motorcycle looking
good, extend its life and optimize its
performance.Before cleaning
1. Cover the muffler outlet with a
plastic bag after the engine has
cooled down.
2. Make sure that all caps and cov-
ers as well as all electrical cou-
plers and connectors, including
the spark plug cap, are tightly
installed.
3. Remove extremely stubborn dirt,
like oil burnt onto the crankcase,
with a degreasing agent and a
brush, but never apply such
products onto seals, gaskets,
sprockets, the drive chain and
wheel axles. Always rinse the dirt
and degreaser off with water.Cleaning
ECA00010
cC8Avoid using strong acidic
wheel cleaners, especially on
spoked wheels. If such prod-
ucts are used on hard-to-
remove dirt, do not leave the
cleaner on the affected area
any longer than instructed.
Also, thoroughly rinse the area
off with water, immediately dry
it, and then apply a corrosion
protection spray.
8Improper cleaning can damage
windshields, cowlings, panels
and other plastic parts. Use
only a soft, clean cloth or
sponge with mild detergent
and water to clean plastic.
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