Since I'm a big fan of the old Rotax air-cooled single, I recently bought this as my "modern retro" ride.
1994 MZ Silver Star Classic 500. 350 lbs. 34 horsepower, counter-balanced, 4 valves, electric and kick starting, 60 mpg. Enclosed chain. Handles excellent, good brakes, very smooth. Only 100 were ever imported, so they're not exactly easy to find. Cheaper than an SR500 in the same condition, much less than a GB500 or new Enfield.