If indeed, the rebuild was done properly, you might still be in the "break-in" stage of things. Piston rings need to have some load put on them to burnish their fit with the cylinder walls properly. Back in the dark ages when I was making a living as a wrench jockey, Perfect Circle recommended seating the rings by doing 10 full throttle accelerations from 30 MPH to 60 MPH after a rebuild. That's assuming the cylinder walls had been properly honed, and a thorough cleanup done of the residue left by the honing process. We used HOT water (almost boiling), Tide laundry detergent, and a stiff bristle scrub brush on the cylinder walls, followed by a boiling water rinse prior to installing the pistons. I found that a toilet bowl brush made a very handy cylinder scrubber. One time when I got in a hurry on a ring job and didn't do an adequate job of cleaning up after honing cylinders, I totally wore out a set of rings on a cross country trip from California to Tennessee- - - -about 2500 miles!
Jerry
