I just got my new k&N p/n 1388 air filter. I put it in the housing and was wondering if I should open or make a new fresh air opening in the housing. I have a 1992 1200 sporster with straight 1 3/4 pipes without baffles. Stock a/c housing. The carb has been rejetted but to what size I don't know.
Thanks in advance.

 

I suppose you don't have to open it up but it probably wouldn't hurt. I drilled the hell out of mine but to tell you the truth I didn't notice much difference.

 

it just creates a LOUDER sucking sound . . . . . IMHO

 

You're not going to gain much in the way of performance by installing a K&N filter in the stock air box. An unmodified stock box just doesn't flow well enough to take advantage of the higher flowing filter inside.

 

Well,
I'll leave it alone then.
Thanks!!