For years Grand Prix bikes featured inline three or four-cylinder two strokes engines, but then in the late 1970s Suzuki found tremendous success with the square-four engine design for its RG500 and for a time that engine configuration appeared to be the future of Motorcycle GP racing. Kawasaki followed into the square four arena with its KR500 in 1980. The bike was one of the first utilizing a true monocoque chassis for weight savings. The bike was raced in GP, most notably with Kork Ballington. The KR500 never won a 500cc GP, but Ballington managed to earn two podiums – Assen ’81 and Finland ’81. Eddie Lawson got his shot at riding the bike in AMA Formula 1 in 1982.He led a good portion of the Daytona 200 before a broken transmission put him out. In addition to its monocoque chassis, the KR500 also featured anti-dive front brakes, which you can see the linkage of on the right side of the photo. The bike proved unreliable for Lawson, but he did finish second at Road America with the machine that season.

The square four of the Kawasaki KR500 GP machine as ridden by Eddie Lawson at Laguna Seca in 1982. (Cycle News Photo Archives)