Yes I am guessing. Theory based on the vane hydraulic pumps that do not
have gearing like the Wankel designed rotary engines. The motor cycle
engine MAY have silicone nitride seals, but I do not know. Lots of Mazda
engines built plus the Audi and Citreon engines and then the Mazda copy
Russian engines. How many of these motor cycle engines are in use?

Dale Davies