I did not think about or know about any of these problems when John McDougall put new bushings in my old cams in 2004.
The old cams had a bit of a line visible, not much, he used a fine stone to remove it.
Without nary a thought in my head other than to have fun, it's covered 60,000 miles since, mostly two up with luggage. It has done lots of big high speed pulls up mountain highways all over western Canada, the US and even one in Scotland!
I think I have maybe adjusted the tappets twice and only a couple thou change at that.
No special holes or redesigned anything.
They run and run.
I did pull the top end down for a looksee last year. One valve guide was loose. Fixed that and measured cylinder taper with an old ring.
Max variation was 3 thou end gap change top to bottom. This translates to about 1 thou of taper.
Hastings rings say it's time to rebore at anything over 12 thou taper.
I'll be 110 and won't have 12 thou variation!
At some point the ring lands will wear out. That's probably a long way off yet.
Change the oil fairly often and there doesn't seem to be much to worry about. I haven't looked in the timing chest. It's making about the same amount of clacking sounds as it was 60,000 miles ago.
Maybe I've just been very lucky, but it seems that if you have a Vincent that is well put together, you can get on and go, no need for much in the way of redesign or re-engineering.
Glen