I'm working on troubleshooting the electrical on a Chinese atv. For some reason the previous owner cut the safety switch and wired it in-line with the CDI power from the alternator instead of having it short the original pin to ground. I'm getting about 50V AC on the alternator power leads and about 0.1V AC on the CDI exciter lead. Does this seem right?

I checked and nothing is shorted to ground within the CDI. I put a new coil on after measuring no continuity from the spark plug hole to the mounting "ear" on the original. Does it matter which mounting "ear" I use on the coil?

Modified atv wiring diagram.

 

0.1v on exciter seems a bit low, but they vary so much you can't be certain. Kill wire part of CDI can go bad, so it won't switch off. Easy fix is to put a switch on either exciter or power lead, from stator. Some CDI ignition coils have an earth terminal, some earth to a mounting lug. As long as the earth is good, it doesn't matter. If previous owner has had to do that kill switch mod, could be a sign that CDI is failing. If the new coil doesn't fix it, try a new CDI. However problem could be that rather low exciter voltage.