gmotor revving high and then idling normal

[blckwlfny1]

my ktm 50 motor was running fine and then, at idle it started gradually revving higher and higher (as if I was slowly turning the throttle) and then it would drop back down to normal only to do it again. it would take about 5 seconds to complete each cycle.
whazzup?

 

[maniac57]

Look for an air leak somewhere or possibly a restriction in the fuel line.

 

[headtrama]

Could be lean , has the weather gotten cooler there . Try moving the needle or put in a richer jet .