By the 1960's the motorcycles that were being sold in the UK were getting long in the teeth. The vertical twin powerplant had been pushed to its technological limits. The drum brakes could not stop the ever heavier machines. Another area where improvement was needed was frames. This was evidenced when two brothers, famed motocross racers Don and Derek Rickman started producing frames on their own and mounting third party engines on them. The machines were so good that all British engine manufacturers stopped selling engines to them. The Rickmans persevered. The frames were in such demand that people were eager to buy them and find donor bikes for the engines. They included dual disc brakes, oil in the frame and improved telescopic forks.
Towards the ends of its existence, the Enfield cycle company had moved all production to the underground quarry in Westwood, Wiltshire after the Redditch plant closed in 1967. In Westwood production concentrated on engines, which were fitted with Velocette frames to yield the Interceptor Series II motorcycle, the only offering of the factory in those latter years. The powerful Interceptor engine was a perfect match for the Rickmans' needs. For some reason, however, a direct deal was not pursued. Royal Enfield sold 200 Interceptor engines to Floyd Clymer in the US (of Clymer auto manuals and Enfield "Indians" fame). It was going to be the first "revival" of the Indian Motorcycle company with the engines being mounted on frames in Italy. Unfortunately, Clymer died, and the engines were stranded in a London dock. Disposal of the engines was left to Clymer's export agents, Mitchell's of Birmingham. They approached the Rickman brothers for frames, and a limited run of Rickman Interceptors were built. A total of 137 bikes and a few prototypes ended up being produced in the end. They were sold in the UK and in Canada, but not in the US due to lack of DOT compliance. Some were apparently smuggled anyway. Burton's Bike Bits keeps a register of Rickman Enfields.
The Rickman frames were known as Métisse, after the name the brothers gave the first frame they built. They were exhibiting their sense of humor, metisse means mongrel. The brothers were inducted to the US Motorcycle Hall of Fame in 2007. Metisse motorcycles exists today, their latest production is a recreation of the motocross bike they built for Steve Mc Queen in the 1960s.