overheating problem please help

[fkmf6]

i have an 05 fse 450 with 840klm's on the speedo. bought it 3weeks ago as a spare bike and ridden it twice, my problem with it is that when it idles for more than 2minutes it pisses coolant out of the overflow tube onto exhaust header, the fan doesnt come on at all even if it boils, there are no signs of water in the oil so i dont think it has done a head gasket, when it runs hot the performance suffers a little. starts first time every time so with minimal klm's on it what could be the problem? should i run a colder plug in her? the bike sat for four years in my mates shed before i bought it flushed the old coolant with new coolant new oil new plug, bike was dropped previously on right hand side radiator and has dent in it next to fan cuold that cause it, any suggestions or advice would be greatly appreciated
Thanks jim melbourne australia

[gasmonkey]

First off, sort the fan issue out.IME check fan relay and wiring.Check that fan works (temp wired to 12v source).Check that connection is clean etc on the sensor at rear of motor.The sensor operates the fan via the ecu and relay.
Ive replaced a burnt out fan and the rest is generaly reliable.I use plenty of wruth electrical contact cleaner too.

[bergerhag]

Replace the radiator cap. Seen many gg 4-strokes with this problem.

[fkmf6]

Originally Posted by bergerhag

Replace the radiator cap. Seen many gg 4-strokes with this problem.

thanks bergerhag done that with a cheap replacement made it worse then put on a original for 3 times the price and seems a bit better

[fkmf6]

Originally Posted by gasmonkey

First off, sort the fan issue out.IME check fan relay and wiring.Check that fan works (temp wired to 12v source).Check that connection is clean etc on the sensor at rear of motor.The sensor operates the fan via the ecu and relay.
Ive replaced a burnt out fan and the rest is generaly reliable.I use plenty of wruth electrical contact cleaner too.

thanks gasmonkey fan seems not to be working tried to earth it out and nothing is happening

[GMP]

Besides the fan issue, check your impeller. Some were a poor grade plastic that broke down even in the cooler running 2-strokes. Consider EVANS NPG R coolant. No FSE here but it tamed my steamy Cannondale making it ridable in the woods.

[bergerhag]

Originally Posted by fkmf6

thanks gasmonkey fan seems not to be working tried to earth it out and nothing is happening

To test run your fan, either use the Technoresearch software or remve the fan relay and jump the connectors. Bike must be running or at least ignition on in the priming phase. For a quick relay test, just swap the two. If the fan relay is bad, then bike wont start if you swap them.

[East_TN_GG]

isnt there a ktm oem radiator cap that is supposed to be good for the 4t's?

[iancp5]

Originally Posted by East_TN_GG

isnt there a ktm oem radiator cap that is supposed to be good for the 4t's?

Yeah but if it's happening when it shouldn't might be worth finding the cause.

[Qui-gon]

Make sure its on the "real " map not the one that passes emmisions. That map runs so lean the exhaust header glow red and will make the engine run real hot.