Hi ,Just read this in the MA museum piece on Geoff Taylors Metisse,
thought it may be of interest or help,
cheers
Noel
"The Triumph variation was not really the poor cousin to the Matchless, as had been demonstrated very effectively in Britain by both Don and Derek Rickman. In fact, the original Mk1 Metisse (French for ‘mongrel’) which was built in February 1959, used a T100 engine in a BSA Gold Star frame, with Norton front forks and a BSA gearbox. That machine swept into history when Don beat the world’s best riders to record the best individual performance at the 1959 Moto Cross des nations at the hallowed Namur circuit in Belgium.
The second, considerably lighter Mk2 Metisse also used a modified BSA frame to house the Triumph engine, with the Matchless variation first appearing as the Mk3 Metisse in 1962. The Mk3 used the Rickman’s own frame design, constructed in Reynolds 531 tubing, and was an instant success. Some idea of the success can be seen from the entry for the 1964 Moto Cross des Nations in Britain, where no fewer than 24 riders were Metisse-mounted."