I read this, and the other engine thread, and it's quite interesting stuff.

My thoughts on it all are somewhat all over the place though.
As part of his motorcycle business, my father spent a great deal of time reboring and honing 4, and of course 2 stroke engines, and generally when it comes to chrome, or as is more common in bikes, nikasil plated bores, there is actually bugger all you can actually do to them come rebuild or rehone time.

For a start, to the guy that used toothpaste on his bore, I would not be worried, I'd say it's a safe bet that toothpaste would barely make a dent in the stuff, chances are it's just a little cleaner than it was before you started.
We are talking about linings that basically outlast pistons, rings, hell even whole engines in some motorbikes, it's tough stuff.

I do tend to agree in general though that it's not really worth touching the liners, at times when they get a little rough with age, you can run a very lite brush hone through it to clean it up a little on bikes, the same may be true of RC motors, I don't really know, but a brush hone does very little to change taper, it's just a cleaning tool really.

The piston lapping idea is interesting, I kind of like the reverse logic about it, plated liners have no real crosshatch like base metal liners, so why not reverse the process and put the crosshatch on the piston?
It makes some sense in a crazy kind of way, also because you can't alter a plated bore to match a piston (the traditional method), make the piston match the bore.

About the only problem I see with it all, is that you can't always count on a perfect bore with a plated liner, I have seen the same story on some bike engines, you start off with a dud bore, and it just chews pistons.
But then it's not like you can do anything about that, so you either live with it, or replace it.

In a perfect situation, you would all start with an oversized piston, and then using very fine measuring tools, carefully hone the piston to exactly match the bore you have.
Or really, the exact reverse of the way it's done with say an iron cylinder on a car or bike.

You know worst case scenario here is you take a piston from a new engine, and just give it a real light outer hone, and then you got that whole cross hatch thing going for you, and maybe a more free and easy piston fit, which is not a bad thing on a race engine (shorter break in time), so I suppose it's not a bad way to go, sounds like it could be worth a try to me...

Hmm, now of course there is thoughts of a proper tool for this, say a reverse hone tool, sprung in rather than sprung out...