A ring upside down, especially the 2nd ring, could do that. Or the oil ring spring. But so could a lot of other things as pointed out.And is this oil or water? Some questions:
Does this get worse if you drive it than at idle?
If you coast to a stop, then start out again, is there a large cloud of smoke? That is a classic sign of an oil leak into the intake system.
Is the smoke pure white like snow, or does it have a bluish tinge?
What ring type/brand did you use? Who honed the bores (and to what grit if you know)?
Have you pulled the plugs and checked there color. Post pix of both sets if any look oily or blacl.
