Ok,
So I have a CB750 K1 and the fork legs tubes were a bit ordinary. Actually, they were stuffed.
Step 1. Disassemble forks, buy new fork legs tubes from David Silvers, try to get new lower fork leg tube pistons etc.
One piston is o.k. and I've found One NOS piston, which is on it's way.
Step 2. Thought it would be great to reassemble as much as I could and use the one good piston.
Step 3. The original fork legs tubes don't appear to be chromed where the piston slides on and the new legs tubes are. The piston won't fit...
Step 4. Post this question. Any clues about what to do next would be great.