The 2024 Kawasaki KX450 has undergone a ton of changes, one of them requiring an all-new exhaust system. We were eager to develop the best exhaust system possible for the new Green Machine.

Working with multi-time GNCC off-road Champion Steward Baylor we were able to really squeeze every ounce of performance from the new KX. Not only performance but installation on the new KX has been optimized. Working around the new KX chassis we were able to make the new oval-port header fit effortlessly.

Performance gains are massive with our RS-12 Signature Series system, adding a whopping 23.8% max hp and an incredible 16.4% max torque. With gains like this some would think that the new KX would be hard to control, not the case. With the help of our hydroformed oval header, our development team has made the power delivery much smoother than stock!

Our RS-12 muffler has loads of features including our PTF insert system that makes changing inserts a breeze and an optimized muffler shape with added volume and brake caliper clearance. Optional spark arrestor SA-21-K available separately.

• Rubber mounted RS-12 muffler dampens vibration to subframe
• 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.
• Improved performance gains with refined power delivery.
• 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.
• New patent pending Precision Taper Fit (PTF) insert ring makes it easy to install and remove sound inserts and spark arresters.
• Works-look matte carbon fiber end cap with industry leading design, innovation and detailing as expected from Yoshimura.
• Carbon end cap covers the RS-12 inner cap, thus improving looks, while providing easier service as compared to other sandwich mounting designs most commonly found in the industry.
• Repack Kits, optional Inserts and Spark Arresters are available for all models