Ktm350

Could have overheated the motor... I would drain the coolant and see whats left and go from there. Worse case scenario you'll have to tear the motor down...

Personally, I would be tearing it down...

Well right now you might only have scoring. With a SOS pad and some contact cleaner on the cylinder you might be good, throw a new piston in and go moto.

Or you could add coolant and go moto and it could be perfect fine...

Or you could add coolant and the motor could scatter which could cost more to fix and also make for having a possible injury...

You could do a leak down as cheap insurance but it would still be hard to know the true condition of the motor...

At this point there’s no saving it (if it’s hurt) as the damage would have occurred already so might as well add some coolant, start the bike first to see how/if it starts... was the bike making any odd noises or change in tone at idle prior to being shut off (other than coolant from the overflow)? Worst case as stated is disassembly of the engine...

Is there still coolant left? The bike is probably fine. It was only 15 minutes and it’s almost freezing cold out.

I’d refill the radiator and see how she starts up and sounds. It’s not like you ran it with no oil for 15 minutes

Id deff fill it up and run it hard so you can sleep easy or grenade it and know for sure.

As long as some coolant was still coming out I’m sure it’s fine,, put in new coolant and change oil for good measure and ride it

so what happened after you tried filling it up? thought about this last night what outcome was..

I have a 17' (same engine)and race hare scrambles. First GNCC at St. Clairsville (mudfest) mine got so hot it shut down. Radiator cap steaming, overflow, the works. Let it cool, started right up. First OXCR with fan same thing. Replaced all hoses, Engine Ice, Ethanol free gas. Just trying anything to keep this thing from grenading. Next race still overheating. What I found out is I need to go faster(more air) and stay out of roost blocking radiator braces. Thought this things toast. Tear down. Valves haven't moved and piston was barely worn 80hrs... Shocked. I've had mine to the point where its losing power at the top of a climb and spewing from every orifice, even shutting down. Fill it up, if its hurt you'll know. Pinging or lack of power. Its probably fine. Change the oil and look for metal shavings.