Another friend of mine --the reason we all had Vespa back then-- could disassemble and reassemble them with his eyes closed, including the engine.
We'd go to flea markets and garage sales around the country looking for Vespa, Lambrettas and even french Solex for sale. Best find was not a Vespa though but a real Honda Monkey Z50.
One day I forgot to put oil in a Vespa and the engine just froze: cylinder expanded in the piston and rear-wheel locked in place. Somehow I didn't crash. I put oil (you typically had oil with you, in a tiny trunk), waited for the thing to cool down: it just started back up (!).
These were the days, thanks for posting that on HN.
P.S: it's really sad we cannot have nice things posted without having the majority of comments being from environmental-jihadists : (