Hey friends! 

sorry if this has been addressed already. I’m getting around to the build soon 1971 HT1-B and hoping to convert to CDI possibly even 12V anybody got any words of encouragement, admonition, or otherwise?
thanks ! 
 

Stock Yamaha magneto is the "energy transfer" design which has been called a "mechanical CDI".  They are simple and tend to be as reliable as a rock in my experience.  

I have a 1964 Yamaha 80 with a magneto that still runs great on its original points and condensor.  After it had sat for decades in storage, all it needed was a quick cleaning of the point contacts with some cleaner and strips of business card to get a nice spark.  

I'm not trying to discourage you from doing what you want to do.  I'm just saying there really isn't a "need".  Especially on a little bike that's not likely to get a lot of miles put on it.  You're not going to gain HP or anything... and in fact a modern CDI might take away from engine power slightly.  (There are about 745 watts per HP.  CDI might use more power and the higher output 12v lighting coils definitely will.  Can be noticeable on a bike that only has a few HP to start with.)

Finding a CDI might be another challenge.  Not sure if VAPE shows them?  HPI might be your best bet but might take some measuring and research in either case as it's not likely there's a huge market for HT1 CDI's.   Not sure if anyone has made a kit.

Whatever you decide, plenty of folks on here to give you a hand.

I agree with MarkT 100% I had one brand new and rode the hell out of it street and lots of trail riding no problems  I bought another one years ago for my son to ride it still runs great now my wife rides it I would keep the original magneto setup 

CDI mag of an AG100 from 1980 on should fit. Ag's are common in Australia, nz, & South Africa I think. Still 6 volt. Nothing wrong with a good old mag though, just saying.