I have a 1984 Yamha Venture Royale. I purchased a gas tank from a 1987 Venture Royale. Unfortunately it did not come with a gas cap. Is there any place I can purchase the gas cap? Also, one of the four carburetors does not appear to be getting fuel. I opened the drain screw and no fuel came out. All the other carbs appear to be getting fuel as I opened the drain screws and fuel came out. As a result the bike will not start. I have good spark to all four cylinders. Will the carb problem prevent the bike form starting?