Basically, I'm hoping for an informed discussion of questions like these with people who do more than bolt parts together, which would mean people who at least own a lathe and mill. However, as I said at the start, it doesn't seem very many people on Britbike fall into that category so this could be a very short thread.
I own a 70 year old lathe but no milling machine....In the last 7 years or so I have built from the ground up aTriumph race bike, a double engine Triumph race bike, a 70 Triumph and 79 Triumph modified street bikes and a BSA A10. All these bikes were built in the American hot rod tradition,stripped of frills with increased engine performance and built from whatever parts suit the situation...You can see much of the work done right here on Brit Bike.Other than actual engine machine work, I did it much of it with hand held tools and blacksmith techniques...But I have cut piston valve clearance notches , honed cylinders and refaced tappets by hand..
So...What do you want to discuss? grin. Seriously, I have learned something from just about everyone who posts here...Even my wife had some good ideas...