My mechanic replaced the air filter yesterday as a part of the full service that didn't get done last fall because he didn't get the filter he thought would be the best in time. This is a carb Bird with Dyno stage 1 and Laser slip-ons. I believe the previous filter used (in another shop) was a standard filter, while this one was a Hiflofiltro, supposedly best for my tuning. But something's very weird. Now the Bird is "choppy" up to around 2800 RPM's in any kind of extra load, like a small uphill. And below 2000 it's basically impossible to use. I have never had that problem before the filter replacement, so if he didn't do anything wrong while replacing it (a pain in the ass on that bike according to him...) I can only conclude that it's the filter. There seems to be at least as much power in the rest of the range, I even feel there may be a bit more on top. But that can of course also be me wanting there to be... Is this simply a case of "get another filter", or is this me getting the full use of Stage 1 from 2800 and up?