While replacing the back tire on my Vespa Bravo, I lost a small centimeter long pin, round on one end and flat on the other, which I believe catches the variator to start the moped. When I try to start without it, the pedals turn freely. I’m new to moped’s, excuse any incorrect terminology... Here’s a picture of the slot where it used to be. I have no idea where to look for a replacement, any suggestions?