Our new RS-4 systems deliver 12% peak HP and 11% peak torque while enabling a more linear, more usable power curve.
With our new systems the blue machine is much easier to handle while providing more power

The work that went into developing the RS-4 muffler has paid big dividends in Off-road Racing; winning multiple Supercross and Motocross titles since it's inception. We've developed the current generation RS-4 based on that research & development, and the result is a unique design that provides an unrivaled combination of power and quiet exhaust tone. The RS-4 features a Polyresonant duplex chamber and two-staged stepped baffle for increased performance, while a carbon cone end cap finishes off its innovative styling.