I just got a 1969 AT1 to go along with the 1970 AT1-B project. The engine is seized up quite tight, which I will need to get going on trying to physically free things up enough to disassemble. My concern is with the starter/generator. Just taking the left cover off shows a great deal of corrosion and rust, which I might be able to combat effectively, but initially my concern at the moment regards what Yamaha calls the "governor", which is the advance unit and, more significantly, the points cam. The one on the '69 looks to be beyond recovery. (The '70 isn't much better, but possible useable) NLA of course. 

On eBay, I see a few later years' starter/generators for sale that physically at least look much better. So, my question:

Can I use a complete newer starter/generator setup on the '69? Seems to me they should be pretty much the same, but I don't want to just assume that. I think I've even seen new rotors and stators, but no new governors for any year.

Even if the armature and stator coils are all ok, the points cam is so bad that even if I really smooth the cam right down, I think the points rubbing block will get worn down rapidly and I'll be resetting the timing weekly.

Thoughts? Comments? Is there a VAPE system available for these? That would be a nice option I suppose (lose the e-start feature though  ).

Appreciate it.

Cheers!

I've not checked myself yet, but don't forget that CMSNL and Partzilla will often show which models shared a certain part, subject to how complete their databases are.

Caution on parts lists in this case...  Yamaha changed the generator/starter and made it slightly larger, perhaps in 1972?  Or 1974?  Don't have time to look it up.  You can absolutely swap the whole assembly.  Some have said the "governor" is not interchangeable between old and new design because the notch that keys it to the rotor is in a different spot.  

The caution is that sometimes the new parts list will show a replacement part that supersedes an old part but won't work unless it's used with other superseded parts or as an assembly.  For example, Yamaha might show the "updated" complete generator system part number on the 1969 AT1 parts list which is the same as a 1976 DT125 assembly.   But that doesn't mean individual components of the 1976 system will work on an original 1969 system.  

VAPE does make a system.  Mako did a write up on it years ago and it might still be here.  

I have a box of AT electrical parts, mostly used solenoids and voltage regulators, and I think there is a nice governor in there if you decide to stay original

 

Thanks Mark and Alan- That is the kind of thing I was looking for. I can and have dug into the parts books, but as you note, sometimes the superseded part # will work fine, and other times it won't. 

I have no reason to believe that either the armature or stator assemblies on this bike are bad (aside from age related, and I won't know that until I put it to use). But I can see the governor is about gone, so very interested in yours. 

Thanks again!