Yoshimura R&D is exhaust sponsor of a few road racing team in the world, and the Japanese company has plenty of experience with the potent Yamaha YZF-R6, even though there hasn't been an official factory sponsored bike fielded, for a couple of year now.
The Yoshimura R-55 MotoGP style full stainless steel exhaust system is one of Yoshimura's most popular exhaust systems. The R-55 exhaust system maintains the classic recognizable Yoshimura design, it's is this design philosophy that inspired several motorcycle manufacturers to adapt a similar design for the creation of exhaust systems.
The Yoshimura R-55 full exhaust system is a work of art. From the stainless steel muffler to the welds on the stainless steel tubing that comprises the rest of the system, everything about the Yoshimura R-55 exhaust is first class. All parts (muffler with a Carbon Fiber cap, header, mid pipe) bold on to the Yamaha YZF-R6 perfectly, and installing the exhaust system is only a 10-minute affair at most. The power output of the YZF-R6 is boosted considerably throughout the powerband. In stock condition, the Yamaha YZF-R6 is already very impressive; but with the Yoshimuri exhaust system bolted on it feels much stronger than many mod YZF-R6's we've tested. There no weak point in the powerband with the Yoshimura R-55 exhaust system installed: low-end, mid-range, and especially top-end are all noticeably stronger than the stock Yamaha exhaust system.
The Yoshimura R-55 exhaust is claimed to sound test at 94.4 dB, but it sounds a bit louder than that. A few years ago, a loud exhaust system was acceptable, but with today's Thai environmental 'noise' regulations, the Yoshimura R-55 exhaust pipe would probably 'just' classify as road legal.
For some weird reason we received the Yoshimura R-55 exhaust system with a stainless steel endcap on the muffler, the current model in the retail channel comes with an Carbon fiber endcap, see the second picture. For more information including prices look Yoshimura R-55 Full Exhaust System