I seem to remember they had some good write ups at the time, very smooth but maybe a bit too quwerky for most. I believe it was a single rotor, strange things, sort of like a two stroke but not really. I think they had some sort of seals on the rotor tips which could wear. I don't know if they need special oil, I know the Norton rotaries did..Rotella?... I know it was expensive. Rare beasts in any form...The Russian made a Ural/Dnepr prototype but it never made it into production.