The number on my airbox matches yours. The overall width of my airbox is 3 13/16". The width between the two inner sides of the swingarm is 4 inches. The bottom left corner of the box almost rests on the engine case that the rear engine mount threads into. When you say yours doesnt come close, do you mean the box sits way above the cable or it sits way off to the side of the cable?
thanks for all your help so far,