imported post
The great air filter debate. My own experience with unifilters is only with my dirt bikes. very good filter for off road. can't see why it would not be good on the road. An oiled foam filter is much better at repelling small amounts of water than a paper filter, and while I have had great luck with K&N filters they are nor water repellent at all. This is probably not really a concern on our wings though, the stock air box does an excellent job of keeping water out. I think an oiled foam filter passes more air than a paper filter but not quite as much as a K&N. That being said, A K&N on the wing may offer longer cleaning intervals which on the 1800's would be desirable, but I don't think you'd notice any performance gain,as the stock airbox is really the limiting factor.