I dont know whats going on with this thing but its running rich. I can clean the plug off and run it for 5 mins or so then it starts blowing black smoke and popping. I knock all the black boogers off the plug again and im back in good shape for the next 5 mins. Is it just a carb adjustment? I put a k&n filter on it a while ago but I figured if anything that would make it run lean.