If I was in the business, it would be different, but I left the business in the early '80's. I can and have done major work, like crank shafts, pistons, rods, transmission gear sets, etc. I have straigthened frames, even changed the rake of the head stock, chopper style. (I never got very good at relacing spoked wheels, so all my bikes get mags) As I aged, I have gotten less interested in spending a lot of time improvising for the lack of tools and work area under a 100 watt bulb in the dark garage. I quit buying blown up bikes and basket cases. I quit taking in side work on other peoples bikes. Now I get a good solid machine and do any maintenance needed to keep it running properly. I'll do a clutch, cams, any lube and adjustments, replace anything that is worn/broken. I would probably even do an engine if it made good economic sense. I have not split a crank case since 2003. If a bike is too tired to be able to cross the country with on short notice, I sell it and get a "fresher" one, do a maintenance on it, and go for a ride.