7. CYLINDER HEAD/VALVES SUPER8 125 Apply engine oil to a new O-ring and install it. Tighten the cam chain tensioner cap screw. Be sure to install the O-ring into the groove properly. O-ring Install a new cylinder head cover O-ring and install the cylinder head cover. Install and tighten the cylinder head cover bolts. Be sure to install the O-ring into the groove properly. Cylinder Head Cover 7-11