KTM RC390 Overheating

Foxy76

New Member
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Hoping someone can help.
We have a 2015 RC390 34000km on the clock that overheats terribly when only riding 10min. However the bike will idle for 20-25min and everything is fine.
We have bled the bike and last time it did this there was a big air pocket we got out but its doing it again. The bike was fine for one ride ride. Now oveerheating again. Also when it gets hot - around 5000 revs it starts jerking...
Any one have any ideas?
What are the symptoms that the water pump has gone?
Do these bikes have heat sensors?
 

kostean

Member
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If the air gets inside of the coolant system there is something wrong with the setup and not surprised it overheats. The system can not have any air inside or the circulation of the coolant will stop. The efficiency might be reduced to a level it does cool off at idle but can not manage under load.

1) Check if the cooling system maintains pressure and the radiator gap is ok. If the radiator cap does not seal properly, it will expel coolant when hot and suck in air when cooling down.

2) If the air gets to fully topped up cooling system- an equal amount of coolant needs to escape somehow, so if it is not leaking via overflow/radiator gap- it does need to escape through other means, and the most probable is the cylinder head. Warm up the engine and rev it, if it bubbles via the expansion tank hose- the head gasket is blown. Also, the bike might expel white smoke then.
 
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