In July 2013, I purchased a 750K3 that's been embalmed in concrete for 27 years - one of the machines from Vancouver's Expo 86 World's Fair.
I got "The Gray" for $100. She had been sitting outside forever. This is a long term restoration. I hope to rebuild the bike to full working order first, then strip her down and repaint her as faithfully as possible to maintain her Expo appearance.
I've got her rolling, the transmission shifts but the motor is seized. I pulled the carbs off, soaked them in gas to soften the latex, power washed away the cement and stripped them down. The first three carbs were in quite rebuildable shape, but #4.. when I pulled off the float bowl it was full of crud like feta cheese. The floats fell out. It's going to be a long slog.