I recently bought a 1998 summit 500 for my son, with a blown engine, so i decided to do a complete rebuild. Got a new crank, connecting rods, pistons. Had a rebuild center bore the out of round cylinders and provide new pistons to match the bore. Put it all together and only had 85 PSI per side. Tore it down again to check specs end gap on piston rings was 26 thou, bore on the cylinder was .758 and the piston was .748. Did my trusted machine shop mess up.