andrew n, one end obviously belongs to the spark plug, the other one to the ignition coil. I do have the repair manual on my fileserver , do feel free to download it. It will show you how to repair and how to take care of your moped. The part number for your coil is 33410-02430 Good Luck.
[http://www.keepandshare.com/doc/2797380/1980-suzuki-fa50-service-manual-pdf-may-9-2011-9-53-am-11-3-meg?da=y|Service manual]
[http://www.keepandshare.com/doc/2797379/1980-suzuki-parts-manual-pdf-may-9-2011-9-53-am-2-3-meg?da=y|parts manual]