First time posting....
I've got a '78 Moby 50V. Just got it last week, first moped for me.
The first night riding I was fine for the first few miles. After that it wouldn't keep firing. I looked it over and figured that the spark plug was losing contact (doesn't have a normal spark plug boot...more like a fork that fits over the spark plug contact). I bent in the forks and she seemed to run fine again.
Also noticed on first night that when the headlight is on, the engine dies at idle speed. I think this is a magneto problem. Tail light doesn't work either.
I ordered a new ignition cable with boot and tried installing it tonight. The HT coil (plastic bit the ignition runs into) has a fixed screw at the ignition port. I screwed on the new cable and covered the spark plug with the boot.
Engine fired over for a little while, but was just barely running. Then died, now doesn't fire again. Swapped back the old ignition cable and still won't fire up.
Is there a good way to measure if I'm getting a spark in the cylinder? Could there be something else wrong with the magneto (seems like some of the wires could be loose)?