How do you tell if it is running rich or lean and how do you fix it. My blaster was running fine for a few weeks and then i put a k&n air filter on it and i think it is running rich but dont know for sure. Any help is appreciated. Thanks

 

If you put on a K&N you'll have better airflow thus a higher air to fuel mix making it run lean. Rejet, its bad for your engine to run like that. If you were running rich your bike could foul plugs faster.