The RS-4 muffler was developed in conjunction with the Rockstar Makita Suzuki Yoshimura race team with one purpose in mind: winning championships. That goal was accomplished during the 2010 AMA Supercross and Motocross season when Ryan Dungey and his Yoshimura-powered RM-Z450 took the motocross world by storm as the first rookie in the history of the sport to dominate both series. The new RS-4D builds on the technology that has made the RS-4 a force to be reckoned with on the racetrack, enhancing its rock solid performance.

The RS-4D boasts a unique dual-outlet design that increases the amount of open area at the exhaust outlet. With dual internal baffles, the RS-4D increases the exhaust gas flow rate, resulting in smoother power delivery and increased throttle control, and offers increased horsepower and torque throughout the power curve, especially in the bottom to mid RPM range where riders need it most. The RS-4D is available as a full system, in either Titanium or Carbon Fiber, and comes with an ultra-lightweight carbon fiber end-cap.

The RS-4D has been in use during pre-season testing by both the Factory Honda and Suzuki SX teams and will be the system of choice for a number of the riders during the 2011 Supercross season. RS-4D systems for Honda and Suzuki applications will be available soon. Check for application updates.

Titanium Full system: $1,045 MSRP Carbon Fiber Full system: $1,095 MSRP
2011 RM-Z450 RS4D
Carbon Part Number: 219201E220
Titanium Part Number: 219201E720
2011 CRF450R RS4D
Carbon Part Number: 225801E220
Titanium Part Number: 225801E720
2011 RM-Z250 RS4D
Carbon Part Number: 218301E220
Titanium Part Number: 218301E720
2011 CRF250R RS4D
Carbon Part Number: 228401E220
Titanium Part Number: 228401E720

To learn more about Yoshimura and view their wide variety of performance products, visit

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