Starter Generator Rebuild
 

What is involved in rebuilding a starter generator? Would that require special tools or anything? The one on my 129 needs to be rebuilt, and I would rather do it myself if possible.

It really depends on what is wrong.
Sometimes they just need brushes replaced.
A true "rebuild" would need the bearings/bushings replaced,the armature commutator turned and the mica between the segments cut.
Also if the bearing surfaces were worn, that needs addressed.
The field coils need tested or replaced if bad or the insulation is burned.
The housing is normally cleaned/blasted and repainted after the fields/pole shoes are removed.
The armature is inspected for shorts between the winding's as well as for grounds on a growler, also a visual inspection for thrown solder where the winding's are attached to the commutator.
as I said, it all depends on what is wrong.
More times than not the brushes wear first.
But after all these years of service, anything can happen.
I have opened up a starter or generator expecting a simple brush replacement and found a burned up, worn out mess.
other times, just the opposite.
Hope this helps with a little visual for you.

Thanks, that does help.