The Voss motorbike

Does anybody know if there is any published information on the make of Werner Voß' motorcycle (the one shown in the famous photo with him leaning against the seat, recently reproduced in Barry Diggens book)? Fiddling around with that published image suggests it may have been a Singer (perhaps a Beute motorbike?!) but that was just a best guess at the squiggle that serves as a logo on the fuel tank. It is often said the 'mercurial' Voß 'tinkered' with this bike... but I have never seen its make written down.

Please, don't tell me it might have been yellow... and try not to mention reincarnation either ;)

Thanks to all in advance.

Stalling,

Ron Dragg