Zoller
Zoller - built a single cylinder two-stroke engine with a pumping chamber making it appear as a twin. Moto Revue, Dec 1927.
"Les premiers essais faits Montlhéry ont donné les résultats les plus encourageants et l'on envisage la création d'une 500 cmc.." (The first tests made Montlhéry have given the most encouraging results and the creation of a 500 cmc.)
Zoller superchargers were fitted to BMW, DKW and AJS in the 1930s.
Sources: Moto Revue, et al.
