 The engine acting as a stressed member of the frame, and most other components in common with the post-war twin-cylinder models.Unlike the twins, it had a Burman BAP four-speed gearbox held by a vertical piece of cast aluminium, which mated with the backbone frame that it shared with the twin models.At the time and to this day some members of the motorcycling fraternity quipped that it was really only 'half of' the desirable Rapide twin-cylinder model, although in fact the specification had more in common with the higher performance Black Shadow twin-cylinder model, sharing compression ratio (7.3