I might just know...since my Ex now has a Babetta (by my best guess of what the hell it is)....this is the one with a Batavus engine ain't it ?
Cause I just might have a line on where to get those.
I dunno about chain guards, but the plastic cap over the Magneto or Clutch...apparently the same cover fits both sides, and but my info runs about $8.00 US each.
Also know a little about how to modify them, but most of the info I know is also covered by that guy with the Batavus page.
Lemme look for the info, and lemme know if that's a Batavus engine on there, allright ?