If you have the one that's in the rectangular airbox, there really is no K&N that fits it without cutting and modifying the airbox.
If you have a round one that is in the toolbox, then you might be able to take that one in to a dealer and match it up with something.
If you want to delete the airbox, and put on a universal pod/cone type filter on the carb, just get one with a 1.75" mounting hole and a clamp.
They are available from NField Gear.
I will warn you that the pod types can cause a "hiccup" in the throttle response at low throttle positions, and they allow a lot of intake noise to be heard when running. They are popular, and look pretty cool, and flow a lot better than the stock filter does, but there can be some issues with them.
For some reason, they seem to work okay on some Bullets, and others have seemingly incurable problems with them. I really don't know why certain Bullets just don't run well with them, even after exhaustive re-jetting work and tuning, and still they have issues. Other Bullets do just fine with them.
Topic: K&N Air Filter size for Iron Barrel (Read 2004 times)