I know its a long shot but when you cleaned the air filter did you put a rag in the intake to keep out dirt, and leave it in? I did it the other day. I even taught to my self "take the rag out", I was doing two bikes, took out the first one, got distracted and left the 2nd. I remembered about 20min later and went in after it. Its probably not your problem but I figured I'd throw it out there.