Thanks to a new petcock from Treatland and a new 12v battery from Pep Boys, the Miyata started right up and ran great. I didn't even need to adjust the idle or idle mixture. The petcock uses a M16x1.0 bung, and luckily some Puch mopeds and Ducatis use this size. It threaded on like a champ, and thanks to a glass fuel bowl in the bottom, it is easy to see fuel flowing.
Now I get to turn my attention to all the little details, like getting some chrome re-finished, making a rear taillight, finding some rear turn signals, and new Miyata script logos for the side covers and handlebars. All the fun stuff.