There is a kit called the freak that is available from newbonneville.com to eliminate the airbox. The box serves two purposes. It smooths the flow of air so that the intake is quieter and so that you get the effect of having a larger filter by giving the air a larger place to be pulled into. When the engine starts pulling air through the filter, there is a pressure drop on the clean air side. When there is a large area to pull air from, the pressure drop is less and the larger vacuum area continues to pull air from the filter after the inlet valve closes so the other cylinder gets more on its intake stroke.
