Lawnboy 18’ish years old, started having blow by and piston slap, so noisy running old girl. I rebuilt it last winter with new rings gaskets cleaned up valves and adjusted lash. Ran good after that, but still noisy and getting worse and blow by is back. I think I need to hone cylinder out a lot more and go with a .01 or .02 over size piston and ring set. Stock piston is pn 40044. Any thoughts on pn of bigger piston and rings and/or idea if this will work?