it has all stock carboration(sp?) and a new top end but wont stay idling. it will idle high but just die out after a while, the rpms just drop. i checked for an air leak w/ a can of wd40 spraying around the carb and head while the engine was on but it didnt seem to do nething. ive been told that too tight of valves could do this but i adjusted them the other day and they seem ok. ill check them again but i dunno if thats it. also what can i use to make a gasket for inbetween the carb body n bowl? the carb is clean also. the gas is old though. could this hinder performence? i dont suspect it though, these xr's could run on desiel. it has a 35 pilot, should i put a 40 or what ever the next step is in?