Topic: Brake calipers / arms ID help

[cobra2411]

I thought I had collected 2 of the same calipers/arms for my dual disc conversion but I realized they are different...

One is a 750 arm and caliper with an approximate 42mm piston. The other has a 38mm piston and the mounting holes are located closer together. CB550?

Here are some pics

[stueveone]

Does one of the have fins and the other doesn't? Honda switched the caliper in 76-77 to a larger piston diameter. It is the better design in my opinion and if that's the one you have, I would find a match.

[cobra2411]

No, they look the same, just one is bigger. I have a finned one on the bike now (K1 front end.)

[scottly]

The caliper with the 42.7 mm piston is from a K7-K8 750. The 38 mm caliper with the narrow bolt holes is from a smaller bike. The K1 finned caliper has a shorter arm than later versions, and also mounts at a different angle. In other words, neither of those will work on a K1 front. You need an early caliper with a matching arm.

[cobra2411]

I have K7 forks that I want to run in my K1 clamps. I'm collecting parts for a dual disk swap. I have 1 K7 bracket & caliper; thought I had 2... Just wanted to confirm the smaller caliper & bracket was off a small bike.