If it runs better without the air filter maybe try getting a better one. I believe the stock one is ok at first but gets dirty quick and wont let in as much air. A foam filter would be great (a 32mm air filter might fit).
I've been running my bike sans air filter. I know I'm risking damage... But it runs and throttles way better. I think I'm going to just put same pantyhose on it. I drive it on the street so it's pretty clean with no dust.
Yeah pantyhose does work really well I've done it before on lawn mowers and things like that. Plus it's a soap in it sheds all debris really easily so doesn't stick into it. We're regular air filters have those Zig Zags in there that catch everything and keep it in there and reduce the flow.