What changed from '75 to '76 to require different bushings?
The collar is a different diameter on the '76 and "F" and later bikes: it is 0.001" larger diameter on the outer half of each bearing area. The cupped washers between the swingarm tube and the frame changed to have seal around their insides. The internal grease seals disappeared and the two phenolic end caps (also called a "bush" by Honda) disappeared. The bushings became longer by 0.24" and the flange was added to press against the new cup washers in place of the previous phenolic "bush"es. The OEM bushings had one groove in the middle, which matched up with the groove on the baring area of the collar, to attempt to retain some grease in the area. It didn't work real well, though: the earlier version lasted FAR longer.
With those bushings that have the spiral groove inside: they will ingest water from high-pressure car wash spray, so if you use them, keep away from those areas when cleaning the bike.
When I last tried a set of those bushings, I found them to be 0.005" oversize on their OD and 0.035" oversize on the ID. It was like they were made for a Kawasaki, not a Honda. they would not fit...when you go to install them, be sure to check these dimensions first. The press fit should be only about 0.0005" to 0.0010" with this type of bronze. After you press them in, you will find they have mushroomed in the area near the inner edge of the flange, requiring that you either bore or hone them to fit the collar again.
