AMC developed the AJS E90 500cc parallel twin during World War Two 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 horizontally laid out motor. However with the banning of forced induction from 1946 the supercharger was never fitted, leaving the design somewhat flawed. About the only major change made to the motor were revised cylinder heads that raised the compression ratio. Power was about 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.
Fine photography by Phil Aynsley
The Sammy Miller Museum is an historically important collection of road and competition motorcycles which focuses on the golden age of the sport in the 1950s and 60s. The collection includes some of the most outstanding machines ever raced, and almost all are in running order. Many have been lovingly restored, and some have been left with their original patina.
More information here: The Sammy Miller Museum