JIMS offers high quality aftermarket performance racing engines, transmissions, & super kits for Harley-Davidson motorcycles.

JIMS USA was established in 1967 in Camarillo, California. JIMS is widely considered the premier manufacturer of aftermarket performance racing engines and transmissions for the Harley-Davidson and custom motorcycle industry.

JIMS Engines

Every design element and every part of JIMS 120” and 131" Race Engines have been developed and optimized to produce a balanced, durable and very powerful racing engine. As it stands, unmodified, the JIMS 120” and 131" Race Engines deliver 135 ft/lbs torque and 130 Horsepower. It is strong enough to produce much, much more. JIMS has concentrated development on building a solid foundation for further modifications. There is enough case material to support a bore size of 4.800", substantially thicker than a stock Twin Cam. JIMS did their homework, built the parts, tested, refined them and tested some more. After thousands of miles and hundreds of dyno hours, the result… JIMS 120” and 131" Race Engines. The JIMS 120” and 131" Race Engines were then sent to a renowned independent test lab and tested some more. They passed. They prevailed. They won.

JIMS proudly offers you the JIMS 120” and 131" Race Engines, the best foundation for racing possible. JIMS has made every effort to produce an engine capable of high mileage. However, drag racing is and has always been our primary objective. Every detail including displacement, cylinder heads, cams, carburetor size and ignition maps have been designed, developed and combined for the single purpose of getting through the lights first.

JIMS Transmissions and Super Kits

JIMS new Fat 5 Overdrive is simply the strongest, toughest gearbox made...Period. JIMS took advantage of its new, more compact shifter technology to increase the width and strength of every gear. The width increase varies from 18% to 53%, depending on the loads each gear set must carry. Big power is more popular than ever. Large engines like the JIMS 120 deliver double the stock power and torque. When such power is linked to the ground through high torque clutches and big sticky tires, the peak loads on transmission gears rise far above what stock transmission gears were designed to endure.

JIMS does Right Hand Drive the right way! JIMS Right Side Drive 6 speed transmissions have the most innovative design, strength, quality, and durability in the industry. They look as good as they work too! A drop in for most major manufacturers frames, the JIMS Right Side Drive is sure to improve your bikes performance as well as its looks. All JIMS transmissions are available as a complete transmission or as a superkit.

All aftermarket performance JIMS racing engines, JIMS transmissions, and other JIMS motorcycle parts are designed to fit stock OEM Harley-Davidson motorcycles with no modifications. Visit www.jimsusa.com for more information regarding JIMS and its family of JIMS motorcycle engines, transmissions, and other drivetrain products.

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