Cooling System; Radiator Cover For The Cold Season; Checking The Coolant Level - KTM 125 SX Owner's Manual

MAINTENANCE WORK ON CHASSIS AND ENGINE
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10 mm
when engine ist cold

Cooling system

The water pump in the engine circulates the cooling liquid. However, the cool-
ing liquid can only circulate properly if the cooling circuit contains no air
bubbles.
Bleeding of the cooling system is therefore required
a) after adding more than 0.25 l cooling liquid and
b) after refilling the entire cooling system.
(see Bleeding the cooling system).
Some models are equipped with a thermostat [1] so that the engine reaches
its operating temperature more quickly. When the engine is cold, the liquid
coolant circulates in the cylinder and the cylinder head. As soon as the
cooling liquid has reached a temperature of approximately 55°C, the thermo-
stat opens and the cooling liquid is also pumped through the two aluminum
radiators.
The cooling liquid is cooled by the air stream. This means that the cooling
effect decreases with the traveling speed. Dirty radiators additionally reduce
the cooling effect.
– IF POSSIBLE, ALWAYS CHECK LEVEL OF COOLING LIQUID WHEN ENGINE IS
COLD. IF YOU HAVE TO OPEN THE RADIATOR CAP [2] WHEN THE ENGINE IS
HOT, USE A RAG TO COVER THE CAP AND OPEN SLOWLY TO RELEASE PRES-
SURE. CAUTION - SCALDING HAZARD.
– DO NOT DETACH ANY RADIATOR HOSES WHILE THE ENGINE IS HOT. THE
ESCAPING HOT COOLANT AND THE STEAM MAY CAUSE SERIOUS BURNS.
– IN CASE YOU GET BURNT, HOLD THE AFFECTED PART OF YOUR BODY UNDER
RUNNING COLD WATER RIGHT AWAY.
– COOLANT IS TOXIC. KEEP THE COOLANT OUT OF THE REACH OF CHILDREN.
– IN CASE COOLANT IS INGESTED, CONSULT A DOCTOR IMMEDIATELY.
– IF COOLANT GETS INTO YOUR EYES, RINSE THEM OUT WITH WATER IMMEDI-
ATELY AND GO SEE A DOCTOR.
A mixture of 50% antifreeze liquid and 50% water is used as coolant. However,
the antifreeze protection must be at least -25° C (-13° F). This mixture offers
antifreeze protection but also good corrosion protection and should therefore
not be replaced by pure water.
FOR THE COOLING SYSTEM, USE ONLY WITH HIGH-GRADE ANTIFREEZE (E.G.
MOTOREX ANTI- FREEZE). USING LOWER-GRADE ANTIFREEZE AGENTS CAN CAUSE
CORROSION AND COOLANT FOAMING.
Pressure induced by heating of the coolant in the system is controlled by a
valve in the radiator cap [2]; a water temperature of up to 120° C (248° F)
is admissible without, having to expect any trouble.

Radiator cover for the cold season

To ensure that the engine reaches its operative temperature also at low tem-
peratures, the radiator cover [3] must be mounted.
For this purpose, detach the left radiator protec-
tion [4] and mount the cover in front of the left radi-
ator as illustrated.
Remount the radiator protection.
NOTE: The radiator shutter can be obtained
from your KTM dealer

Checking the coolant level

The coolant should be 10 mm (0.4 in) above the radiator fins when the engine
is cold (see diagram). In the event of the coolant being drained, always fill
and bleed the system.
IF POSSIBLE, ALWAYS CHECK THE LEVEL OF COOLING LIQUID WHEN THE ENGINE
IS COLD. IF YOU HAVE TO OPEN THE RADIATOR CAP WHEN THE ENGINE IS HOT,
USE A RAG TO COVER THE CAP AND OPEN SLOWLY TO RELEASE PRESSURE.
THE COOLING SYSTEM MUST BE BLED AFTER DRAINING THE COOLING LIQUID
OR AFTER ADDING MORE THAN 0.25 L (0.06 US GALLONS) COOLING LIQUID.
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