I used to get them made by Safetek in a material that would run 'wet', so the clutch cover wasn't needed...
However, after many years use my single spring clutch was completely worn out so I changed to the 4 spring Triumph unit for which all parts are readily available....Details of that conversion would take up another post, although it's quite simple, but it's an option you might consider if your current clutch is badly worn....It's not cheap mind....Ian
If it eases your mind that same clutch was used on motorcycles with near twice the Hp of an M20 so it is more than good enough
It was used on the pre-war B series as well and there it was 1 set of plates shorter because the B's were "medium weight sports" bikes where as the M clutch was supposed to be able to haul a 1/2 ton of sidecar + load .
Post WW II nothing odd to see one with 2 x 44 gallon drums of oil or a 1/2 ton of coal in a commercial box sidecar .
