Cooling System; Checking The Cooling Liquid Level - KTM 990 SUPER DUKE Owner's Manual

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 liquid. When the
engine is cold, the cooling liquid only circulates in the cylinders and cylinder heads. The
thermostat will open when the engine reaches approx. 75°C (167°F) and the cooling liquid
will also be pumped through the aluminum radiator.
Cooling is by means of the air stream. The lower the speed, the lower the cooling 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 COOLING LIQUID TEM-
PERATURE WARNING LAMP [3] WILL LIGHT UP WHEN THE COOLING 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:
3 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 TEMPERATURE IS 120°C
(248°F) AND THE IGNITION IS ON. IF THE FAN IS NOT WORKING, 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 BOTTOM 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 LIQUID 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
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