Steve, I bought a PVL German digital ignition for my 83 YZ125K. I wasnt cheap but it replaces the stator, rotor, coil and cdi. All bits fitted straight on with no hassles and after i timed it, the bike started second kick and run like a beast. Why bother with 32 year old electrics and risk ruining your day. I have a few pics up in the Yamaha section on this site under YZ125K rebuild of what the system looks like and how it is fitted.
Cheers,
Alex