I am rebuilding the break calipers on a 1977 cb750f . The pistons are rusted and I am looking for the part numbers to replace them. I think that they were rebuilt before and installed on wrong wheel. The FRONT left has one caliper that piston that is larger and the right front is smaller. The rear has also has the smaller piston like on front right.

What is the size or part number for the piston (like K&L)?

What is the rebuild kit numbers for the larger and the smaller pistons?

I assume the larger caliper/piston goes on the back correct not the front left. Correct?

Thnaks for your time in advance