Well there sure seems to be a lot of hating on a guy who just posted something a little different for us all to check out and enjoy. Who's to say what's "cool" or not especially regarding how fast it is or isn't and what kind of burnout is acceptable? We're all a bunch of adults playing with half retarded old mini scooters that most other folks would laugh at us just to see us riding/wasting time and money on. I appreciate the unique motor, and the history of all these bikes. Bottom line, if he's having fun, and not hurting you in the process, then keep the judgements to yourselves and enjoy your own bikes, and other's for thier differences.
Personally, I grew up street racing riding shotgun with my Dad in his built and torbocharged RX-7 and that little car was a RIPPER. I'd love to lay hands on one of these old Sachs motors just to play with it.