Yoshimura has been working tirelessly on development with American Honda HRC's engineers to achieve maximum performance and mass centralization, to optimize rider usability. Yoshimura achieved all this by moving the new RS-9T mufflers forward in order to tuck in under the side number plates. Working with HRC race engineers and the all-new engine and its unique downdraft fuel injection system, Yoshimura was able to deliver an exhaust that provides more tractable power and improved torque. Serious fun for the small bore. Significant power gains with the RS-9T full system. Made to look like the big brother CRF's with the RS-9T muffler. Repack kits, optional inserts and spark arresters are available for all models. Stainless steel header and tail-pipe.