Thanks for all the great suggestions folks. It wasn't the clutch slipping (already changed that before). I think the fuel problem was pretty close, ie. the bowl was emptying faster than the pet cock or tank could refill it, but the problem wasn't consistent, sometimes it "died" and other times ran fine........hmmmmm. not indicative of a blockage.........so what was it ????????? It was a faulty coil (no points here). When the coil got hot, it would start failing, so I would lose spark, Then it would start working again.......suddenly now I've got power. The engine wouldn't restart after 1/2 hour of riding, again overheated coil. I was almost at the end of my rope !!!
New coil $45USD. Now she runs like a top.........35mph and I've got bugs on my teeth. (from smiling).
Thanks for the help everybody.