Only had a few mopeds; 2 expresses, a PA50 II, and Motobecane 40V
My 40v runs a rebuilt engine; the donor cylinder is a 65cc autisa kit with a cast-iron sleeve. That with a malossi intake and a SHA 15:15 make that bike the fastest off the line of the bunch.
The horn/light switch on mine was iffy, but in the end it was a matter of carefully disassembling the switch, cleaning the brass contact/switch balls, and it's worked fine for years since.