![Yoshimura Rs-4 Exhaust S/O Ss-Al-Cf KTM 250/450SXF 11-15 350SXF 263502D321](http://roco4x4.com/cdn/shop/files/c01a6204-07c8-42e6-8367-1b3f1e8f86e9_1.208623d09296105ae973af0c934a8d6f_9ffbb477-7a51-4bd8-b11b-797550f5f937_993x700.jpg?v=1715411899)
![Yoshimura Rs-4 Exhaust S/O Ss-Al-Cf KTM 250/450SXF 11-15 350SXF 263502D321](http://roco4x4.com/cdn/shop/files/c01a6204-07c8-42e6-8367-1b3f1e8f86e9_1.208623d09296105ae973af0c934a8d6f_9ffbb477-7a51-4bd8-b11b-797550f5f937_993x700.jpg?v=1715411899)
Description
The work that went into developing the RS-4 muffler design paid big dividends in 2010 with Ryan Dungey winning the AMA 450 Supercross and Motocross Championship series as a rookie in the same year, and again in 2012 with the Yoshimura-backed GEICO Honda team winning both 250 Supercross Lites titles. That same R&D has been directed to developing the current generation RS-4 - a unique design that provides an unrivaled combination of power and a quiet exhaust note. The RS-4 features a Polyresonant duplex chamber, a two-staged stepped baffle and an innovative carbon cone end cap.