Bought a set of MC std piston rings for the 71 CB750 because the oil ring is the old style rather than the newer three piece design. They come with a thin 'undersprung' ring shim that I assume goes in the oil ring land before the oil ring is installed to make the oil ring "thicker". So is this an optional part or should I just put it in there? Research suggests use the shim for honed bores but that's as detailed info as I can find and I've not seen other mfgs offer this shim. Can someone shed some light on this? Oh and one of the rings has a gray edge which I assume is the non-polished chrome top ring but the rings came with no explanation whatsoever and Rusty Rider aint talkin.
