I have a question regarding front brake calipers. I have two CB750 bikes, one is a '71 the other is a '74. The older bike has a seized engine and we are using it for a parts bike. I suspect the bike has lived in Colorado all of its life, so a lot of the parts are in pretty good shape. The '74 runs and this is the bike my son and I are rebuilding. The '74 came from San Diego and it has more surface rust, also the PO let the bike sit for 8 years in his garage and the front brake was seized on the disk. I have finally been able to get both calipers apart and remove the brake pads and piston. (I did successfully use the grease gun method for both calipers.)
The caliper on the '71 is a bit cleaner and the piston has very little pitting on it whereas the piston on the '74 is not as nice. I noticed that the caliper on the 71 has a 2 on the body where as the 74 has an eight; and the piston on the '74 is machined differently. There is a recessed area on the '74 while the '71 is smooth. The picture shows that.
Given this difference I am wary of using the '71 piston in the '74 caliper. Honda no doubt improved the front braking system from '71 to '74. While there is some pitting on the '74 piston is it safe to use or should we just buy a new piston?
