I have a 1976 CB550F and I cant seem to fund a switch assembly that is the same. I want to reuse the top section of my switch with the turn signal switch because it is still nice. The lower half has the mirror mount broken off from when my dad had the bike, probably happened in the late '70s. I have one used section from a 77 cb750, different, one from unknown year cb750 ( I guess they thre it in for free), and one from a 75 cb550 and it is different. It doesnt seem to fit to the top half of my switch worth a darn. And my old one has a very small notch for the neutral switch and the 75 doesnt. I dont think it sits in there completely flush without it. Hooked it all up any way and everything works but my turn signals. Only the rears blink and only about every 3 -4 seconds. Sorry for the lenghty post. I might add I reused my old switches which worked fime before I swapped the lower case.