HIRO KOISO RACING RAISES THE BAR ONCE AGAIN AT THE BONNEVILLE SALT FLATS

Hiro Koiso Racing, renowned for engineering the fastest sit-on Harley-Davidson in history, has officially concluded its intensive 2026 campaign at the legendary Bonneville Salt Flats by setting a remarkable new AMA national record of *233.742 mph in the 3000 APS-PBF class. Smashing the previous record of 211.032 mph—which had stood since 2014—the team continues to push the absolute limits of two-wheeled aerodynamics, engine tuning, and mechanical endurance in pursuit of unprecedented performance.

Entering the 2026 Bonneville Motorcycle Speed Trials with a heavily optimized, supercharged 2006 Harley-Davidson Dyna-based motorcycle, the team faced the unforgiving salt course with a relentless drive for engineering perfection. At the heart of the machine lies a custom-built 135 cubic inch Twin-Cam race engine by JIMS and T-Man Performance, paired with a high-output ProCharger system and a brand new JIMS FAT6 transmission, featuring specialized WPC metal surface-treated internals and Worldwide Bearings, delivering staggering horsepower to the rear wheel. Every component, down to advanced chassis configurations, has been meticulously refined to conquer the unique traction challenges of the salt.

"The salt demands absolute precision, respect, and relentless preparation," said team owner, builder, and rider Hiro Koiso. "Every year we learn more about how the machine interacts with the shifting surface. Our recent passes have proven that our power delivery and aerodynamics are right where they need to be. Pushing the boundaries of speed on a sit-on bike isn't just about the numbers for us—it’s the culmination of years of engineering evolution, late nights in the shop, and the unyielding support of our partners."

The 2026 campaign highlights Hiro Koiso Racing’s ongoing commitment to pushing motorcycle land speed racing into uncharted territories. As the team analyzes data from this season's runs, preparations are already underway for future record-breaking attempts, leveraging cutting-edge telemetry and aerodynamic refinements to cement their legacy on the flats.

Hiro Koiso Racing extends its sincere gratitude to its core technical partners and sponsors—including Red Rock Harley-Davidson, JIMS, T-Man Performance, and ProCharger—whose dedication to high-performance innovation makes these historic assaults on the salt possible.

About Hiro Koiso Racing

Based in Las Vegas, Nevada, Hiro Koiso Racing is an elite land speed racing team specializing in high-horsepower Harley-Davidson platforms. Led by veteran engine builder, tuner, and fabricator Hiro Koiso, the team now holds 24 land speed records, including 16 AMA and 8 FIM records, continually redefining what is possible on a sit-on motorcycle.

(*the new record is pending ratification)

Hiro Koiso Racing Is powered  by:

Red Rock Harley-Davidson

JIMS

T-MAN PERFORMANCE

ProCharger Superchargers

サードプレイス Performance Division

Dynoman（ダイノマン）

Horsepower Inc.

HRD Performance

WPC Treatment

Frixion,

MKS Engineering, Inc. / TRUEONES

Fuji WPC

Dunlop Motorcycle Tires

Worldwide Bearings

Lyndall Brakes

Sundance Enterprises,Inc.

True-track

Cometic Gasket, Inc.

Custom Cycle Engineering

45Degrees

Darkhorse Motor Company,

Shoei Helmet

Hyod Products

Fullgain,

DJB Gas service Inc.

Ram-Proline

Motul USA

Jaggers Construction

ARP

Photo credit: Taka Masui Photography