AJS Motorcycles

Today in Motorcycle History

AJS Porcupine 1946

AJS Porcupine

AMC developed the AJS E90 500cc parallel twin during WWII from a Joe Craig concept. It was designed from the outset to be a GP bike only and was to feature a supercharger mounted above the almost horizontal engine. Supercharging was banned in 1946 leaving the design somewhat flawed. The engine received revised cylinder heads which raised the compression ratio, delivering power of around 40hp at 7,600rpm. The spiked finning on the heads brought about the nickname of "Porcupine". The bike debuted at the IOM in 1947 but suffered from carburation woes and the tendency to snap magneto drive shafts for several years before it finally found success in the inaugural World Championship season of 1949 - becoming the only twin to win the 500cc title. The design was substantially revised in 1952 and named the E95.

Bill Doran, of Shropshire, became a works AJS rider in 1949. He rode the 500cc "Porcupine" to victory in the 1949 Belgian Grand Prix.

On July 7, 1951, Doran won the 350cc Dutch TT on a works AJS.

He crashed during a Thursday evening practice for the 1952 Isle of Man TT resulting in a broken leg. The accident occurred on the left-hand bend after Ballig Bridge and was renamed Doran's Bend.

Sources: todayinmotorcyclehistory.blogspot.com, Fine photography by Phil Aynsley