i have a 77 maxi ive been putting together. the taillight {brakelight works fine, i just unplug the brakelever switch to ride around} the little grey wire is the mystery, the light comes on if i hook it up to the yellow {headlight} wire, so its not anything stupid, it sparks well and everything else works good, i checked around the flywheel, points look clean, is there any good way to be sure all that's working properly besides throwin a hundred bucks down on a 12v cdi? help me out and i can help you out too, mail me a busted tailpipe i'll mail it back nicely welded whole again. THANX HOLLA!