DJ-3290 Honda Rings STD GX390

HONDA  Standard Stock Size Piston Rings 88mm bore 13010-Z1C-800. 2mm Top ring X 2mm 2nd ring x 2.7mm 3rd ring. 
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.