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Price doesn't include shipping* 

Parts that are not in stock can be ordered by emailing or contacting us*




  • Pentagonal-shaped sleeve
  • Front muffler cap functions as a polyresonant chamber which helps reduce noise
  • Two-stage stepped baffle
  • Carbon fiber end-cap
  • Stainless steel header and tail-pipe



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.


RS-4 STAINLESS/ALUMINIUM SLIP-ON: The RMX450Z off-road bike is bred from the race winning RM-Z450, but the RMX450Z is a fuel-injected torque monster built to perform on the trails. Add a Yoshimura exhaust into the mix and you've got yourself an unbeatable trail machine. The RS-4 muffler is a unique design with predicated power, a side benefit of a quiet earthy exhaust note that speaks volumes for performance. It was an obvious choice for the RMX450Z.

Slip-On comes with a stainless steel tail-pipe, aluminum muffler sleeve, installation hardware, and detailed step-by-step instructions.

Stainless Systems come with an AMA-approved sound insert.


PIM2 Unit (2010-2012)Yoshimura introduces PIM2, the evolution of our original Dirt Bike/ATV fuel injection adjustment “PIM” device. PIM2 installs easily, typically in under 30-minutes using simple Plug-N-Play technology. Plug the PIM2 into the stock wiring harness, mount to your bike using the supplied mounting kit, and you are ready to race! The PIM comes pre-loaded with two separate fuel injection maps for either a Yoshimura Slip-On or Full Exhaust System. But the adjustability is limitless and easy. If those two maps are not enough - there are dozens of maps


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