Maybe I'm missing something. What exactly is the controversy?? American Superbikes all have direct roots to production street bikes and, not surprisingly, each eligible model represents the most powerful motorcycle available from top manufacturers such as Suzuki, Honda, Yamaha, Aprilia, Buell, Ducati and others. The big-bore bikes all produce at least 1000cc in engine displacement from a variety of twin and multi-cylinder powerplants. Four-cylinder, four-stroke machines have a minimum post-race weight of 375 pounds and are limited to 1000cc engines, such as the Suzuki GSX-R1000, Honda CBR1000RR and Yamaha R1. Two-cylinder, four-stroke machines must tip the scales at a minimum post-race weight of 390 pounds but can exceed 1000cc in displacement, such as the Buell 1125CR and Ducati 1098R.