There are definitely some area's of the clutch that should have the slightest amount of lubrication, especially anti-seize, the bushes and so on should not be set up so as to have minimal clearances, or else the clutch can give trouble. Interesting point about the twisting action of the plate carrier acting on the C20 nut, but there are equal loads either side from two shoes, and the bush in its center should be very lightly lubricated at assembly. I have worked on and rebuilt many of these clutches now (by far the best clutch for a Vincent twin) and I feel that generally the C20 nut comes loose because it is not done up tight enough, this may be because owners see the need to align the slots in the mainshaft with one on the nut, and simply nip it up like they would a front wheel bearing on an older type of car/trailer wheel hub. And also that the factory gave little in the way of torque figures for any of these nuts, not unlike the ESA nut. Most folk these days have no "Feel" as to how tight something should be tightened to, as these trades/skills slowly disappear.......... Some people on this forum including myself will be the last of that generation.