Boyesen Internal Engine Parts

Boyesen: A Legacy Built on Reed Induction Innovation

Few names in performance powersports carry the same weight as Boyesen. Founded by engineer Eyvind Boyesen in 1972 and headquartered in Lenhartsville, Pennsylvania, the brand was born from a single patent and a relentless drive to extract more performance from two-stroke engines. His patented dual-stage reed induction technology delivered results that spoke for themselves — motorcycles equipped with Boyesen reeds consistently outran the competition both on and off the race circuit, cementing the brand's reputation as a leader in intake induction performance.

Boyesen's internal engine parts remain the cornerstone of the brand. Reed valves, reed blocks, and Rad Valve intake systems are engineered to increase airflow and air velocity, improving acceleration and top-end power across a wide range of two-stroke applications. Whether it's the Carbon Tech dual-stage reed for maximum reactivity and longevity, or the Pro Series reeds combining a carbon fiber top reed with a durable fiberglass bottom, Boyesen offers a tiered lineup to suit everything from recreational riding to factory-level competition.

As four-stroke engines became dominant in motocross and off-road riding, Boyesen expanded its engineering focus to address a new challenge: heat management. The result was the iconic Supercooler — a high-performance engine water pump cover and impeller kit that has become the benchmark for bolt-on engine cooling upgrades. The Supercooler is specifically designed to enhance the performance of an engine's cooling system, using a high-flow, hydrodynamic design tested to move more coolant and keep the engine running at a more constant temperature. Boyesen's patented nautilus-style impeller is 25 percent more efficient at moving water than a typical stock impeller.

Beyond the impeller itself, Boyesen's engine cooling pumps and accessories extend the Supercooler system with investment-cast aluminum covers featuring enlarged water inlets, sculpted internal geometry, and reduced cavitation. The investment-cast aluminum water pump cover features bigger water inlets, a sculpted design, no casting seams, less restrictive corners, a more efficient impeller, and less cavitation. Reducing engine temperatures helps extend the lifespan of valve-train components and other heat-sensitive internal engine parts.

Boyesen has captured the attention of Kawasaki and Yamaha Factory Racing teams, leveraging their engineering and manufacturing mastery to create water pump covers and impellers, ignition and clutch covers for both two- and four-stroke dirt bikes, ATVs, snowmobiles, and watercraft. Their comprehensive line of aftermarket bolt-on upgrades spans Yamaha, Honda, Kawasaki, and Suzuki platforms from the early 1980s through today's most popular models.

From the race shop to the trail, Boyesen's commitment to precision engineering and performance-driven design has made them a trusted choice for riders who demand the most from their machines. Whether you're rebuilding a vintage two-stroke or dialing in a modern four-stroke MX bike, Boyesen has a solution engineered to perform.