Do I NEED to run a prefilter on it? I still have the stock one but I would appreciate it if someone could point me in the direction of where to get an outerwear for it.

 

K&N spent millions of dollars researching and building a quality air filter to run by itself. Why would anyone choke it off with a prefilter. I had a 25 year motorcycle shop mechanic tell me the worst thing you can do to a K&N is put a prefilter on it. You would be better off with the stock air filter and no pre filter than running a K&N with a prefilter. Trust the K&N it needs no help it will filter the air all that is needed.

 

Ok, I don't have much shop experience but, if you are talking about the outer ware sock, I think it keeps you from cleaning the filter more often. I have it on my K&N and just rinse it out. Helps allot after dusty rides.