As for parts, that will be tough considering the age. You can try to find some on ebay. Collectors tend to have parts and occassionally put them up for sale.
As for the engine, I think rebuilding would be tough in terms of replacing parts. Maybe if you take the engine apart and inspect it you can get it to run again. If not, you may have to adapt a new style engine to it.
By the way, who is Franko?