Look, just use a bastard file on the the port edges and you avoid problems. The larger the ports, the more the ring slightly falls in the port. The chamfer brings it out unharmed. The bastard file allows you to get the rounded corners.
As others have said, a quick run through with a ball hone, and filing (easing edges) is not needed, but should still be quickly inspected if a HO motor including PWC engines.
As others have said, a quick run through with a ball hone, and filing (easing edges) is not needed, but should still be quickly inspected if a HO motor including PWC engines.