This was a tiny 50cc motorcycle derived from an earlier design originally intended as a children's ride at an amusement park, but later adapted as a small and light runabout for more general use. The Z50A was the second production version, introduced in 1969, and had slightly more reasonable 8" (200mm) wheels instead of the 5" (125mm) ones on the earlier Z50M.
The model as published is to the scale 1:11, but as usual I reduced it to 1:14. At the reduced scale the tubular parts (frame, handlebars, exhaust pipe) were nigh-on impossible to make, so I redrew them in a somewhat simpler style. I also adjusted slightly the proportions of the frame to match better to the photographs of the original that I could find, and made one or two other minor modifications.
The result is a charming little model, less than 90mm long.