2002 YAMAHA DT125R check engine

6-15
PERIODIC MAINTENANCE AND MINOR REPAIR
68. Install the reservoir tank hose.
9. Pour the recommended coolant
into the radiator until it is full.10. Install the radiator cap.
11. Run the engine several minutes.
Stop the engine and recheck the
coolant level in the radiator. If it
is low, add more coolant until it
reaches the top of the radiator.
12. Install the radiator cap stopper
bolt.
13. Fill the reservoir tank with
coolant up to maximum level.
14. Install the reservoir tank cap and
check for coolant leakage.
NOTE:
If any leakage is found, ask a
Yamaha dealer to inspect the cooling
system.15. Install the cowling and the panel.
EC000080
cC8If coolant is not available, use
distilled water or soft tap water
instead. Do not use hard water
or salt water since it is harmful
to the engine.
8If water has been used instead
of coolant, replace it with
coolant as soon as possible,
otherwise the engine may not
be sufficiently cooled and the
cooling system will not be pro-
tected against frost and corro-
sion.
8If water has been added to the
coolant, have a Yamaha dealer
check the antifreeze content of
the coolant as soon as possi-
ble, otherwise the effective-
ness of the coolant will be
reduced.
Recommended antifreeze:
High quality ethylene glycol
antifreeze containing corrosion
inhibitors for aluminum engines.
Antifreeze and water mixing ratio:
1:1
Total amount:
1.05 L
Reservoir tank capacity:
0.35 L
3MB-9-E8 6/13/01 10:55 AM Page 52

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
3MB-9-E8 6/13/01 10:55 AM Page 54

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
3MB-9-E8 6/13/01 10:55 AM Page 55

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
3MB-9-E8 6/13/01 10:55 AM Page 66

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)
3MB-9-E8 6/13/01 10:55 AM Page 67

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.
3MB-9-E8 6/13/01 10:55 AM Page 69

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.
3MB-9-E8 6/13/01 10:55 AM Page 76

6-44
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.
3MB-9-E8 6/13/01 10:55 AM Page 81