I have a CB550 and when I tried to adjust the cam chain, the screw is stuck. From what I have seen, the screw should not move when turning the nut. Mine moves with the nut. I tried holding it with the screwdriver while loosening/tightening the nut but can't keep it stationary. I am getting a chain rubbing against metal sound from the engine. Not only that but I cannot get it above 70mph. At the top of each gear it loses power until I shift up. Rides fine until it hits the top of the gear and repeats loss of power.