Also see page 139 of 'Into the Millennium' to see a picture of the mod I described earlier. Note that this can be done which ever type of main shaft and nut you have and totally does away with any need to seal the outer end of the shaft.
OK, rather than putting information on the forum that I believe to be correct as opposed to knowing that I am correct, I made a call to Steve at Maughan and Sons, the clutch seal modification for B + C series Vincent twins is still available, it is possible that when this mod was done by them they might have cleaned the face of the C20 on a lathe to give a smooth surface for the O ring to mate with, this would not have been done to intentionally dimensionally change the length of the C20, but it is possible that in doing so the C20 does in fact become unusable if you want to revert to the C18/1 bonded seal, so in essence Hugo you were correct, in the past I have got round the problem of a too short C20 by having a little material turned off the thickness off the flange, enough to accommodate a decent thickness C19 shim without locking up the clutch centre, alternatively buy a new C20 from Maughan and Son, they are a thing of beauty, almost to good to put a spanner on.
What issue of MPH is this mod described please?Also see page 139 of 'Into the Millennium' to see a picture of the mod I described earlier. Note that this can be done which ever type of main shaft and nut you have and totally does away with any need to seal the outer end of the shaft.
I have been using the C18/3 mod for many years, probably forty by now although it didn't have a number then , being supplied by the late Tony Maughn. It is easy to fit, and does work, no need for that horribly bodge of gasket cement on the splines.So this new seal C18/3 with aluminum spacer to slip on G3 and the oring to go to the outside of the new C18/3 spacer would appear as my out of scale rough drawing?
The theory being that oil would not leak down the C20 threads?
maybe thread sealant?
Looks like a good design. Anyone successfully using C18/3?
This C18/3 seal also allows me to ignore the C3 mod, which I think is a good design as well.
View attachment 25326