Saw a posting on another forum I monitor that might interest members here.  Max BMW in New Hampshire is building a 1975 BMW R90S motorcycle using only new parts sourced from BMW's stock of vintage replacement parts.  There are Facebook and web sites available that document the build.

http://www.maxbmwmotorsport.com/max_bmw_r90s_build/

Live webcam  at http://www.maxbmwmotorsport.com/r90s

Be quick; the build is expected to take 4 days.