Join Date: Jun 2000
Location: Chandler, AZ, USA
Id say keep the stock filter.
The RAM air is a finely calibrated setup. And you may find that the K&N filter for your bike is the same size as stock, but whereas the stock filter has the foam element across the ENTIRE face of the filter frame, the K&N may only have a small square opening on the comparatively large solid rubber filter frame. K&N does this on some bikes because an increase in top end RAM air without extensively retuned needle steps and slopes will really destroy any performance gains from the K&N.
So basically K&N detunes their filters on certain RAM air bikes to have the same flow characteristics as stock units. (i know they did this with the ZX6E, which has the same RAM setup as the 93-95 ZX7R, and ZX11E)
Nonetheless, you would still get the longevity of the K&N. But dont expect ANY performance increase.