I have this 1974 CB450 which I reassembled last fall. Bored cylinders, new pistons, new rings and a professional valve job. Afterward I found that the left cylinder compression is like 170 and the right is about 80. I can't figure out why. Valves were all adjusted to spec. New gaskets and rings correctly spaced. Would a missing cylinder stud gasket affect this or are those more about oil control?