Hi, I've just picked up my first MZ project, a 1977 250 partly dismantled and not used for many years. There are two incomplete engines, one with vertical head fins, one horizontal. Am I right in thinking that the horizontal fin engine will be a 5 speed? Are parts interchangeable (not the gears I know), I'm thinking particularly of the cylinder and piston?
I'd like to use the horizontal fin engine but it's piston is missing.