OK, for all of you that own the 1981/1982 Honda Express SR NX50.
The clutch assmbly that goes over the shaft that does into the back wheel is DIFF BETWEEN THE TWO YEARS.
I have 81 and bought one off what we (me and seller) think is a 82. The bearing set up in them is diff from one year to the other. Unless you look real close at them you don't realize it till you try to put it on. I can only assume that they changed the way they did it at some point.
The bearing openings are diff sizes between them, the type of bearing they use if totally diff. The machined groove that holds the retainer clip for the bearings is in the 81, it is NOT in the same.