2017 Superbike Track Shootout

The Kawasaki and Yamaha are at the bottom of the curve when it comes to midrange horsepower production. Note how the power of the CBR (after being the highest-output four-cylinder in the 7000-8000 range) flattens out after 10k rpm, followed soon after by the ZX, GSX-R and R1, so that they are able to pass the EPA’s noise-emissions regulations by partially closing throttle plates at high rpm. The Euro bikes are seemingly unaffected, showing massive power advantages at the top end of the curves. “The EPA noise regs are probably doing more harm than good,” rants Duke. “Frustrated owners of affected bikes can get their ECUs reflashed for immediate power gains costing just a few hundred bucks, and since they’re already modding their engine, they may want to add an aftermarket exhaust system, which is likely to be louder.”