When Honda came out with its CB750 in 1969, it brought new levels of sophistication to the street. But while the 750's four-cylinder power and disc brakes were big advances, the bike's frame, flimsy by today's standards, was still a limiting factor.
AMA Motorcycle Hall of Famers Derek and Don Rickman made it better.
Here’s what they did.
The Rickman brothers started out as motocross racers in the 1940s, improving their British-built race bikes, and their finishing positions, by building lighter, stiffer frames. When they couldn't get anyone in the British motorcycle industry to show interest in their innovations, they went into business themselves.
By the 1970s, British manufacturers were dead or dying, and the Rickmans had expanded to produce frames for a variety of dirt, street and racing motorcycles, including Honda's hot new 750.
The buyer of a Rickman CR750 chassis got a frame made of exotic manganese molybdenum steel tubing, a stiff swingarm with a proprietary chain adjustment system, cafe racer-style fiberglass bodywork, clip-ons, rearsets, a replacement front fork, and upgraded brakes and wheels. Just slot in a CB750 engine, electrics and controls and hit the street to impress owners of ordinary motorcycles.
Of course, with all that going for it, a Rickman CR kit wasn't cheap. In fact, it cost $1,495, or the same price as a complete CB750. That, plus the limited nature of Rickman production, made a CR750 one of the most lustworthy machines of the early 1970s.
The bike boasted a 736cc air-cooled SOHC transverse-mounted inline four engine that pumped out a claimed 67 horsepower at 8,000 rpm. Carburetion: Four 28mm Keihin.
Top speed? About 110 mph. Wheelbase: 56.5 inches. Dry weight: 439 pounds. Transmission: 5-speed, chain final drive.
Frame: Reynolds 531 manganese molybdenum steel tubing. Suspension: Betor telescopic forks front, twin Girling shocks w/adjustable preload rear.
Tires: Dunlop TT100, 3.50 x 18 front, 4.25 x 18 rear.
At Mecum Auctions recently, bidding went as high as $14,000 for a 1975 Rickman CR750.