KTM Super Duke 990s - Manual (Page 37)

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MAINTENANCE WORK ON CHASSIS AND ENGINE
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Cooling system
The water pump in the engine ensures a forced circulation of the cooling liq-
uid. When the engine is cold, the cooling liquid only circulates in the cylin-
ders and cylinder heads. After the engine reaches the operating temperature
(approx. 75°C, 167°F), the thermostat opens and the cooling liquid is also
pumped through the aluminum radiator.
Cooling is by means of the air stream. The lower the speed, the lower the cool-
ing effect. Soiled cooling fins also impair the cooling effect.
If, for example, slow urban traffic or waiting at a traffic light cause little or
no air to stream through the radiator, the temperature of the cooling liquid
will rise. The radiator fan [1] switches on when the cooling liquid reaches a
temperature of 102°C (216°F). Additional air is blown through the radiator
to prevent the cooling system from overheating.
THE TEMPERATURE INDICATOR [2] WILL BEGIN TO BLINK AND THE RED COOL-
ING LIQUID TEMPERATURE WARNING LAMP [3] WILL LIGHT UP WHEN THE COOL-
ING LIQUID REACHES APPROX. 120°C (248°F), HAVING EXCEEDED THE NORMAL
OPERATING TEMPERATURE. POSSIBLE CAUSES:
– SLOW RIDING WITH LARGE LOADS AT A HIGHER AIR TEMPERATURE:
IF POSSIBLE INCREASE YOUR RUNNING SPEED, SO THAT MORE AIR CAN BLOW
THROUGH THE RADIATORS. SHOULD THE WARNING LIGHT STILL BE ON OFF
AFTER 1500 METERS (1 MILE), STOP IMMEDIATELY, SWITCH OFF THE ENGINE
AND LOOK FOR OTHER POSSIBLE CAUSES.
– THE COOLING FAN ON THE RADIATOR IS NOT WORKING:
THE COOLING FAN MUST BE RUNNING, WHEN THE COOLING LIQUID TEMPER-
ATURE IS 120°C (248°F) AND THE IGNITION IS ON. IF THE FAN IS NOT WORK-
ING, AND THERE APPEARS TO BE SUFFICIENT COOLING LIQUID, THE ONLY
THING YOU CAN DO IS TO DRIVE ON TO YOUR NEAREST AUTHORIZED KTM
WORKSHOP AT THE LEAST POSSIBLE ENGINE LOAD.
– TOO LITTLE COOLING LIQUID IN THE SYSTEM:
CHECK WHETHER ANY COOLING LIQUID IS LEAKING OUT (ALSO ON THE BOT-
TOM OF THE MOTORCYCLE).
LET THE ENGINE COOL DOWN AND CHECK THE COOLING LIQUID LEVEL IN
THE RADIATOR (SEE CHAPTER CHECKING THE COOLING LIQUID LEVEL IN THE
RADIATOR). ONLY CONTINUE TO DRIVE IF THERE IS ENOUGH COOLING LIQ-
UID IN THE SYSTEM. CONTACT AN AUTHORIZED KTM WORKSHOP TO HAVE
THE ERROR ELIMINATED. YOU WILL DAMAGE THE ENGINE IF YOU CONTINUE
TO DRIVE WHEN THE COOLING LIQUID TEMPERATURE WARNING LAMP IS ON.
– EXCESSIVE USE OF THE CLUTCH AT SLOW SPEED
A mixture of 50% antifreeze and 50% distilled water is used as the cooling
liquid. How-ever, the anti-freeze protection must be at least -25° C
(-13° F). Aside from antifreezing protection, this mixture also provides great
corrosion protection which is why it must not be replaced by pure water.
– FOR THE COOLING SYSTEM, USE ONLY HIGH-GRADE ANTIFREEZER (MOTOREX
ANTI-FREEZE). USING LOWERGRADE ANTIFREEZE AGENTS, CAN CAUSE COR-
ROSION AND COOLANT FOAMING.
– MORE ANTIFREEZE MUST BE ADDED IF YOU PLAN TO TRAVEL TO A REGION
WHERE TEMPERATURES ARE EXPECTED TO DROP BELOW -25°C (-13°F).
Pressure induced by heating of the cooling liquid in the cooling system is con-
trolled by a valve in the radiator cap [4]; a water temperature rising up to 125°
C (257° F) is admissible, without fear of problems.
Any excess cooling liquid caused by thermal expansion is conducted to the
compensating tank [5]. It will be sucked back in as soon as the temperature
in the cooling system drops.
Checking the cooling liquid level in the compensating tank
Check the level of the cooling liquid when the engine is cold. It should fall
between the MIN and MAX marks on the compensating tank [6].
Add cooling liquid (see above for mixture ratio) if the cooling liquid level drops
below the MIN mark.
If you need to add cooling liquid quite often, the cooling system may leak. If
the compensating tank is empty, also check the cooling liquid level in the
radiator. Have the cooling system checked by an authorized KTM
workshop.