is it all stock? stock jetting, airbox ect. if so it's either a clogged jet or bad gas. gotta really watch the *Edited**Edited**Edited**Edited* gas they have out nowadays with a 2-stroke, alot of it has alcohol and other oxengenates and crap in it. wich will make you run lean. was the fan working?
and how were you riding it? wide open on a lake or breaking a trail for a long time, or just riding on groomed trails?
could have lost a crank seal, base gasket, intake gasket, who knows.
proper maintenence, jetting and good fuel is the key for a reliable sled.
85 atc 250r;
PSI porting & head mods
fmf pipe & silencer
boysen rad valve & reeds
38mm air stryker