Pretty sure the Mono means "one" as in one cylinder
NO !!!!!!!!!!!!!!
Sorry I am not normally this blunt, but monoposto and biposto simply refers to how many bums the bike can seat.
Posto means seat with respect to Italian bikes, whatever the make/brand.
Mono = one and Bi = two Seats in this thread, nothing whatsoever to do with number of cylinders.
Richard
My personal posting rules ...
If I really know the answer I will post.
I might post potential solution or whatever if there have been no responses.
If there have been have been some plausible guesses I might add some plausible guesses as well.
If I have no effing idea I won't post.