bought some air filter foam in a sheet from my local bike shop and cut it to fit my mc18 r5k air box. but the bikes running rich still, could it be that this cheap foam isn't letting through as much air as a standard filter?
it seems quite dense .would buying a standard filter from honda solve the problem or is something else causing the rich running? the sj's are 38's?
any ideas chaps?
dunk.

Is the foam oiled or dry? I have seen filters with too much oil do this. Typically a foam air filter in a NSR requires a re-jet.