I've got a1981 cb900c and have no compression in one cylinder except when the engine is running. Then the cylinder has some compression in it. I'm assuming this means that the head gasket is bad. I've ordered the parts and tools already so if anyone doubts this diagnosis please let me know so I can cancel the order. I don't have a lot of extra money but I need the bike running since I have no other transportation. The exhaust valves have no clearance either so I'm going to have to adjust that. Waiting on tool so I can figure out what size shims to order. I'm thinking this isn't the problem with the compression.