Thanks - very interesting!
He gives rather odd performance figures. With 1100cc, allegedly the biggest two stroke motorcycle engine, the quoted 84Nm torque makes sense for an engine that size. But why only 28hp power? Must be very low RPM.
And that fits with the text in
https://www.blick.de/erzgebirge/baerens ... el12383835, where he says: 'I've driven a hundred, but it's best driven at 80 km/h.' Going fast was not his objective, but he wanted a special home-made bike - and succeeded well!