Clearing the valve clearance To remove the battery negative cable and the ventilation hose to the cover. Take time to disconnect the throttle linkage and lay it aside. Use a plastic hammer (only when necessary) to break the gasket seal without scraping off the sealing surfaces and remove the cover retaining bolts as well as the cover out of the engine. Clean the mating surfaces on the cover gasket on the camshaft, check and correct nicks and gouges, the rubber gasket should be not hard or cracked, replace it as required. The next step is to put in place the cover and gasket, attachment bolts, and tighten them, as recommended. Install throttle linkage and ventilation hose and replace battery cable. Lastly, ensure you check throttle operation and then put the vehicle back into operation.