Alpha Bearings of Dudley is an engineering company that manufactures parts for engines, still in business today. In the early 1960's the small but powerful Villiers 197cc engine was being used for racing. As more and more power was extracted from it (they got to around 30 bhp!) stock parts kept on failing. Alpha stepped up to the plate supplying better parts. This eventually led them to decide to produce entire engines, called "Centuri" (there is little information out there and I'm not sure if this is a typo or not). Alpha was part of the E H & P Smith conglomerate that owned, among other companies, Royal Enfield and Albion Gearboxes at that time. Due to this relation the Alpha Centuri was fitted into an Enfield frame, as shown in the picture. Apparently Royal Enfield was not happy about this. They eventually settled for a GP5 frame, but Royal Enfield demanded that the frame not be modified, which lead to a sub-optimal placement of the engine. With the demise of Royal Enfield's own racing effort, Starr engineering got the dynamometer that had been used to tune the GP5. With a Centuri engine and a new frame, reminiscent of the GP5, Hadley, an unpaid helper at Alpha collaborated with Starr and continued development. The bike proved fast but fragile, and the Albion gearbox with its false neutrals proved a hindrance. Eventually the project was canceled in 1968 by E H & P Smith who decided to pull out of racing entirely. Read about recent attempts to restore a Centuri here.