After some web searching of several forums and videos (took me way too long) I think I’ve narrowed down what the shifting problem is in the 1985 Honda ATC 125M (the transplant to my 1984 CT110).
The nice thing is it sounds like a fairly easy fix and the part isn’t too expensive. I guess I’ll be doing a video of the inspection and fix if that is what it ends up to be.
Lots of good advice on http://www.3wheelerworld.com
This was a good thread that has some good pics as well
I found a better pic in the service manual
It looks as if this is the same part that lives in my CT110 engine so if I need to replace it maybe I’ll just borrow it from the CT.
Update to this problem, it was the shift drum stopper. I guess on the 1985 125M it is a problem. We used vintage CT90 shift drum stoppers to fix the problem in these old ATCs. Search for the “Z Calls it the Fat Bastard” video to see the fix.