^
@Jim well the link says Tropfen (or 'drop', for its aerodynamic form)
1953 (??), but the photo itself claims it to be from 1923, which it is. I heard some allied soldier found it after WW2 in a garage somewhere and took it with him.
Yes, that is it, built by Max Schueler (including the engine and all).
It was called the Tropfen (drop) Motorrad, and not much were built. When WW1 was over, Max Schueler wanted to fly but was forbidden by the Versailles treaty.
The photo with the LVG biplane on the photo with Schueler, Lorinser and a third pilot was taken at Netter Heide aerodrome.
He had just taken the plane from another abandoned aerodrome and flew it to his hangar, 'illegally'.
Schueler had thrown out the MG, ammunition and was able to carry two passengers, for leisure flights (and money). Soon after the control commission demanded the plane to be destroyed, so Schueler was looking for other opportunities..
His motorcycle was ok to drive, but the fairing (thanks Eichhörnchen) was always tattering and bumping against the frame, so it could be heard from quite a distance
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Before the war, Schueler had held several german and international records, first with an AGO (Otto) biplane which he took up to 3500 meters, in 1913.
Over to you, Jim