what kind of air filters have you tried? the airboxes can be drilled out, like i mentioned. the little cone shaped caps can simply be removed, and wire used to hold the screen in for better performance sometimes. foam filters should be oiled.hi flow paper filter pods pretty much just mean you gotta work with the jets. I've run my Puch for years on many a long trip and rally without any filter whatsoever, with no problems - knock on wood.