I've been remiss, I'm afraid, in reporting back. As it turns out, moped headsets don't include locknuts (as was conjectured above). Still, I ended up buying one from the supply shop suggested in SF since it was local and cheap. I figure at the very least it'll solve the issue of the off-kilter adjustable race. For now, though, since the work-around that I had hit on previously (running the old headset without a spacer, with the locknut lightly tightened) seems to be working just fine, we've decided to leave well enough alone until it becomes a problem (i.e. locknut and/or adjustable race loosens). I also took the step of filing down the top of the old adjustable race so that the locknut lies more flush atop it. If that doesn't hold, we'll probably replace the headset with what we've got, using some Locktite on the steerer tube.

Still, it's great to know that there's a Plan C: ordering a full headset from Germany. Great detective-work, martl. I really appreciate the help! In fact, that goes for everyone. When I first posted on this issue, I was all but hopeless. Hard to believe how much help I've gotten! Here are a few shots of the complete bike (more on my blog):


IMG_0794 by a. rosario, on Flickr

IMG_0796 by a. rosario, on Flickr

IMG_0807 by a. rosario, on Flickr