I was unaware that Harley-Davidson ever produced a 50cc motorcycle, but they did, as shown by this ad in the July 1966 issue of Popular Mechanics.  Despite the Young America monicker, the bike was actually made in Italy, where only 10,500 rolled off the assembly line.  Helmets apparently weren’t a thing back then, but a cape was.  They started at around $225, which works out to $2319  in 2026 dollars.