Not Bagging.....But What Is Up With

[Simmo737]

You can boil a gas gas easy if you punish the clutch and use an oil it doesn't like, the gg clutch seems to like semi synth, full synth like motul transoil expert doesn't hook up as well and gets grabby when td hot then just slips and will boil the bike - did it twice last week, changed the oil and it stopped.

[twosmoker]

i have owned 5 ktm s 250 and 300 s , and have never had any of them overheat , about 15 harescrambles , and many hours of tight rocky gnarly singletrack , i dont really have much bad to say about ktms , but i like gasgas too .......

[GasGasDreamer]

i'm not sure but I think ktm has a higher psi radiator cap so they run at higher temps, so maybe they are 'closer' to boil over ??

I had fluid pump out of my GG once, then I tightened the cap and never again.
I like my '06 expansion tank behind the number plate too and sometimes that will get some fluid in it. I also have an overflow that captures and returns fluid but I have never seen the bike use it.
of course maybe i'm not in the 'real' hot areas, i'm only las vegas, nv and gets 120F in the shade, and I do ride it that stuff and in the slow technical snotty stuff.

[n_green]

I think the modern 2st KTMs also run about 250ml less coolant then equivalent GasGas. But as Simmo said the Gasser will still boil. Just about every ride I go on these days I hear it bubbling away after a long techy hill.

[twowheels]

KTM water jackets have shrunk to tiny volumes, and this can work if you keep the water pump spinning. Grunting up hills and through deep mud or sand simply adds too much heat (or heat too quickly).

There may have been an inherent advantage to the old sand-cast cases as well in their ability to draw heat away from the cylinder and expel it, but that's speculation.

[swazi_matt]

i also think the layout of the bike does not promote easy air flow on the ktm. If you look at it you will see the gas tank is very close to the back of the radiator, the GG on the other hand has very little restriction behind the radiators.

In this part of the world most of the ktm's are fitted with fans. I also fitted one on my GG, but for the record before fitting it i only boiled at the top of the climbs where the ktms were blowing steam halfway up already. (Unfortunately if i forget to turn the fan on in tight situations the bike boils much easier now that the fan cowling reduces flow when the fan is not on)

[shang]

I frequently boil my 300. But usually in the warmer summer months and when the going gets really rocky and slow. Abusing the clutch a bunch. I did put a cooling fan on mine but since it's cooled down it hasn't ever kicked on. We will see when it warms up outside.