Piston size question

[Houstoncb750]

Hello fellow cb750 owners just bought a 1979 cb750 dohc in November and I already took it all apart for a restoration/cafe racer build.
I’m in the search for a new piston replacement since piston number two is pitted from my guess a piece of a spark plug.
I noticed there is different size such as standard size, 0.25, 0.50, 0.75, and 1.00mm.
Any idea which specific size I need before I buy? Don’t want to get the wrong one and not fitting properly. Thx

 

[amc49]

There is no way to tell that without actually being there to view the damage directly, if bad enough none of those will work. It depends on the depth of the deepest pits there.

You also may well find out that the common overbore sizes you see there may no longer be available at least from Honda.

You can always go to the max, or the 3.00 mm. overbore from a Wiseco piston set. Exoensive though. But then everything there will be.