OP here, just filling in some requested details.
In the particular situation I am working on, I have a saw with 100psi cold compression, which runs ok wide open, and will not idle, nor start easily.
Plug fouls often, though mixture is right.
Upon inspecting the piston and cylinder, there are moderate scratches in both.
IMHO, I don't think that the cylinder is ready for the junk pile. it seems likely that if we can carefully remove those cylinder scratches, and add a new piston and ring, we have a good chance of getting back to something closer to 150psi.
There is no way I'm going to reassemble without removing those scratches, and I don't think anyone would recommend it.
That leaves my choice between trying to hand sand those scratches with some 220 paper, followed by some 400, or the seemingly controversial flat stone hone or ball hone for some super light honing. If we could get away with removing maybe a half a thousandth that would seem ideal, as most cylinder specs I've seen are +- a few thousandths anyway. Any plating is typically going to be 3-4 thousandths at least, so that plating remains intact.
I just don't anticipate a new ring seating well against a cylinder without some light honing. I'm also interested in some light deglazing. I understand that a lot of guys use scotchbrite, and that could be an option - though I've not tried it. Honing makes sense to me because you can do as little as you feel you need, and you are assured that you will have a consistent cylinder wall finish - fully around the circumference of the cylinder, as long as there's a light touch.
Hand sanding will be typically concentrated in one spot, and that makes less sense to me than a light, but even treatment with a hone in careful hands.
As I mentioned earlier a certain microscopic roughness in the wall is what is specified by most 2 cycle manufacturers. Most firms finish the cylinder with a diamond hone at the factory and all I've seen, leave intentional fine or microscopic roughness when they are done. All saw manufacturers even have roughness ratings within their factory specs! A highly polished, completely smooth bore, free of ultra fine scratches or ridges is not something I have seen on 2 cycle saws fresh from the factory.
If anyone want to know more about roughness specs I can provide a link to some tech info from Sunnen. They are the company which knows more about cylinder bores and specs than any company in the USA.
Regarding seized pistons and cylinders that seems an easier call. In my experience I would either try to lightly hone the cylinder provided that you can remain within the bore specs, or I'd replace the cylinder, if a replacement was available.
