I just obtained a 1975 CB550 that was parked in a garage in 1981. It seems that the gas may have been run out or drained, but could have just evaporated. Someone "knowledgeable" about these said that something needs to be done with the valves before starting to prevent interferance, but I didn't catch what he said. I want to resurrect this bike to sell it, but now I'm nervous about trying to start it without dealing with the valves. Any suggestions what to do before putting gas in and trying it? Thanks.
