Greg, because you always need an oversized piston if you bore the cylinder, I think it would be more convenient to just find a better one and install that. Honing can be OK if you do it well enough, and if the bore is scuffed, it is essential. I've literally never used my boring head, for any purpose at all. Shouldn't have bought it I suppose.
I think it is difficult to get to the bottom of your oily combustion chamber without replacing the rings to see if it makes a difference. I'd check the breather, and if it's OK, try to compare the amount of crankcase sludge with other similar engines. Has the engine been over-filled with oil?
