2002 YAMAHA DT125R engine overheat

3-3
INSTRUMENT AND CONTROL FUNCTIONS
3
EAU01652
Coolant temperature gaugeWith the key in the “ON” position, the
coolant temperature gauge indicates
the temperature of the coolant. The
coolant temperature varies with
changes in the weather and engine
load. If the needle reaches or enters
the red zone, stop the motorcycle
and let the engine cool. (See page
6-45 for further instructions.)
EC000002
cCDo not operate the engine if it is
overheated.
EAU03889
Turn signal switch “4/6”
To signal a right-hand turn, push this
switch to “6”. To signal a left-hand
turn, push this switch to “4”. When
released, the switch returns to the
center position. To cancel the turn
signal lights, push the switch in after
it has returned to the center position.
EAU00129
Horn switch “*”
Press this switch to sound the horn.
1
2
1. Coolant temperature gauge
2. Red zone
EAU00118
Handlebar switches
EAU03898
Light switch “9/
'
/:”
Set this switch to “'
” to turn on
the auxiliary light, meter lighting and
taillight. Set the switch to “:” to turn
on the headlight also. Set the switch
to “9” to turn off all the lights.
EAU03888
Dimmer switch “&/%”
Set this switch to “&” for the high
beam and to “%” for the low beam.
2
1
3
4
1. Light switch “9/
'
/:”
2. Dimmer switch “&/%”
3. Turn signal switch “4/6”
4. Horn switch “*”
3MB-9-E8 6/13/01 10:55 AM Page 15

5-4
OPERATION AND IMPORTANT RIDING POINTS
5
EAU00436
Engine break-inThere is never a more important peri-
od in the life of your engine than the
period between 0 and 1,000 km. For
this reason, you should read the fol-
lowing material carefully.
Since the engine is brand new, do
not put an excessive load on it for the
first 1,000 km. The various parts in
the engine wear and polish them-
selves to the correct operating clear-
ances. During this period, prolonged
full-throttle operation or any condition
that might result in engine overheat-
ing must be avoided.
EAU00453
0–500 km
8Avoid prolonged operation above
6,000 r/min.
8After every hour of operation,
stop the engine, and then let it
cool for five to ten minutes.
8Vary the engine speed from time
to time. Do not operate the
engine at one set throttle posi-
tion.
500–1,000 km
8Avoid prolonged operation above
7,000 r/min.
8Rev the engine freely through
the gears, but do not use full
throttle at any time.
EC000060
cCAfter 1,000 km of operation, the
transmission oil must be changed.
1,000 km and beyond
The vehicle can now be operated
normally.
EC000053
cC8Keep the engine speed out of
the tachometer red zone.
8If any engine trouble should
occur during the engine break-
in period, immediately have a
Yamaha dealer check the vehi-
cle.
3MB-9-E8 6/13/01 10:55 AM Page 36

6-13
PERIODIC MAINTENANCE AND MINOR REPAIR
64. If the coolant is at or below the
minimum level mark, open the
reservoir cap, add coolant to the
maximum level mark, and then
close the reservoir cap.
EW000067
wNever attempt to remove the radia-
tor cap when the engine is hot.5. Install the panel.NOTE:
If the engine overheats, see page
6-45 for further instructions.
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.
Coolant reservoir capacity:
0.35 L
3MB-9-E8 6/13/01 10:55 AM Page 50

6-45
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.
3MB-9-E8 6/13/01 10:55 AM Page 82