parky

I'm nearing the end of an LC2 rebuild and have everything running and sorted apart from the ignition cut out. On checking it looks like I have a later F model CDI unit which has no Black/White wire going to it. This just happens to be the switched wire from the cut out and ignition switch on the loom. I tested the B/W wire and hey presto it earths when the switches are operated. The question is how do I get this to kill the sparks on the CDI with no B/W wire?? Suggestions (other than a new CDI unit) will be gratefully recieved. Chris