i am into cz/jawa motorcycles and i was cruising around and found a site on the cz/jawa motorcycles. within that site is a guy who stated he had parts for almost any jawa moped.
i forget exactly what he had but it sounded like alot of soft parts like gaskets, piston,rings and such. i would give it a try.
i had a jawa and i could never find any parts for it but then i found this ...
hope this helps