Evolution Of The Norton Manx

By Seth Richards - January 08, 2019
Credits: Richard Drift aboard the four-valve Molnar Manx Evo. The Evo produces 70 bhp at the rear wheel at an impressive 9,500 rpm and weighs only 275 pounds wet. Talk about an evolution. Pete Morris

The British spirit of refinement, born of thrift, is exemplified by one of the greatest racing motorcycles of all time: the Norton Manx.

By 1949 and the start of the FIM Grand Prix World Championship, the single-cylinder racing motorcycle already seemed antiquated. But in the struggling economy of post-war England, it was impossible to invest in the modern tooling necessary to bolster a wealth of new ideas. There’s a reason you never hear about Velocette’s 54 x 54mm four or Norton’s DOHC, liquid-cooled four—they never got off the ground. Innovative plans couldn’t contend with empty coffers.

Pluck and pragmatism would have to be enough.

By limiting the scope of their development to one existing cylinder, engineers became experts in the minutiae in order to find speed wherever they could.

As Cycle World Technical Editor Kevin Cameron points out, years of refinement would turn the Manx into “a very detailed elaboration of a simple concept.” Much like a formal English garden, he adds.

Rex McCandless’ famed “featherbed” frame and hydraulic dampers challenged conventional wisdom of chassis design and were implemented for the 1950 Isle of Man TT. After Norton motorcycles finished first, second, and third in both the Junior and Senior races, the world built its machines in the image of the Manx, and the Manx itself was given a new lease on life. The next year, Geoff Duke won the 500cc World Championship on a Works machine.

Norton continued to invest in McCandless’ notions of weight distribution and aerodynamics for the next-gen racer (known as the F-Type). It would feature a horizontal cylinder, a five-speed gearbox, a lowered frame, and a streamlined fairing. However, for 1955, under the ownership of Associated Motor Cycles Ltd. (AMC), Norton factory racing shuttered its doors, and the F-Type was never produced. It was the end of the Norton Works racing era, but not the end of the Manx.

Norton continued to produce 30M and 40M Manx bikes for privateers, and the boffins found ways to keep them perennial contenders. Larger brakes here, decreased stroke dimensions there—evolutions that all added up to be enough to keep them winning. When Hailwood won the 1961 Senior TT on a Manx with a Jaguar plain-bearing con rod and one-piece crank, it was the last time a single would win the blue riband race on the island. With typical British wit, Motor Cycling’s sincere and biting headline ran: “Private Norton Beats ‘Privat’ MV.”