The most anticipated 450cc motocross bike for 2021 is here! With an all-new designed chassis and engine, the new Honda CRF450 is sure to set new records. Our new RS-12 system for the new Honda CRF450 has been in development for over a year, no stone has been left unturned in our efforts to innovate and create the best exhaust system available. In collaboration with Honda Japan, HRC Honda and MXGP World Champion Tim Gajser, we were able to deliver! The Yoshimura RS-12 and the 2021 Honda CRF450—made with one goal to provide the most precision tuned machine in motocross competition. Developed and tested in collaboration with HRC Honda Racing World Champion Tim Gajser and engineers the new RS-12 is ready for the race track and trails. Aggressive intelligently designed, the RS-12 asymmetrical shaped muffler allows maximize capacity and incorporates a resonance chamber for managing sound and increasing usable power. RS-12's unique profile also provides more clearance for tire and brake caliper. Unique oval manifold design was created using FEA process (Finite Element Analysis) and produced using state-of-the-art hydroforming process Improved performance gains, weight reduction and fit when compared to previous generation design Just like the works systems our Factory Racers use, RS-12 systems utilize precision machined joints. Machined joints provide a superior and exacting fit for joints by better securing the seal between two surfaces with a perfect 360 degree contact surface which translates into improved system life, fit and performance Works-look matte carbon fiber end cap with industry leading design and innovation end cap detailing as expected from Yoshimura Carbon end cap covers inner cap mounted design improves durability, and eases servicing as compared to other sandwich mounting designs most commonly found in the industry New patent pending Precision Taper Fit (PTF) insert ring makes it easy to install and remove sound inserts and spark arresters Tapered muffler body inlet design of RS-12 enables the system to be pushed forward thus helping with weight centralization without sacrificing performance Proudly designed, developed and made in the USA! Repack Kits, optional Inserts and Spark Arresters are available for all models