HONDA Original Parts These rings are .020 Over Standard and can be used with an oversize piston or used as file to fit on a .010 over or standard piston LOOK CLOSE! The chamfers on these rings, especially the one on the compression ring, make these rings superior to anything else available for these engines. This compression chamfer is VERY important as it utilizes the combustion pressure to force the compression ring into the cylinder wall giving the best possible seal. This is a necessity to get higher performance out of long-lasting chrome-faced rings. "Gas ported" pistons seek to achieve the same goal.