Tappet clearance adjusting cover coupled with secondary air valve

An inlet and outlet structure above a cylinder head comprising;

• a tappet clearance adjusting cover having a bottom side disposed on a tappet clearance adjusting hole of a cylinder head;
• a secondary air valve comprising a recessed element and a cap wherein a bottom side of the recessed element is coupled to a top side of the tappet clearance adjusting cover, a bottom side of the cap is coupled to a top side of the recessed element for forming a receiving space between the cap and the recessed element, and the cap and the recessed element are formed with assembly holes at corresponding positions thereof respectively;
• a one-way valve received in the receiving space;
• an inlet pipe coupled to the recessed element at a position between the bottom side of the recessed element and the top side of the tappet clearance adjusting cover;
• and
• a plurality of securing elements passing through the corresponding assembly holes for securing the cap and the recessed element of the secondary air valve to fastening posts disposed at the top side of the tappet clearance adjusting cover respectively.