I've just bought a 1981 Yamaha moped. The model is "Bop II" (in the UK
anyway). It is styled like a "monkey" bike - small wheels, shaft drive. The
engine, final drive and rear wheel are in one unit pivoted to provide rear
suspension. It has telescopic forks and a single rear spring / damper. The
tank is under the seat.
Any further info. (handbook, workshop manual or personal experience of it)
would be extremely useful.