The A3 Engine on my old Golden Bullet TTLX had a crapload of mileage on it, I do not remember offhand how much, but it was somewhere over 6k...and the odometer broke not long after that...bout 6 months later the ped that engine was on (and I was on) was mangled by a car, and I dismounted the engine and rigged it to another frame, and put prolly somewhere past 15k total on it....bastard still ran last time I saw it, too.
Moped engines prettymuch run forever.
-Ree