My opinion is that the K&N filters are not good for the top end, letting in too much grit. People use them to let the engine breathe better, but to do that requires that the filter mesh be larger than the stock paper filters. Plus, they don't really work best until they accumulate a fair amount of oily grit on the mesh. For some reason that just doesn't make any sense to me.
These bikes don't really have the kind of horsepower to tap into. Often times, people through money or effort at the bike but don't find any measureable differences. Maybe at the upper end of the RPM band, but not many people I know try to operate these bikes there for very long.
Sorry, no help with your questions, but good luck with your mods.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Any advice would be appreciated. Thanx. Airhead
Airheads benefit from a long intake tract and the air-box does have a positive effect on power and torque production. In fact, if you really want some cheap horse power, install one of the square air-boxes with the plastic horns on your bike. That can be worth as much as 2 HP under the right conditions. No kidding...
You can also pick up a little power on top if you drill a hole in the baffle but you'll have to get back t me about the exact dimension, cause I just don't feel like looking it up right now.
Unfortunately, most of the stuff that guys do to increase the performance of Airheads, just make the bikes run slower and wear out faster.