Honda 14721-P2A-000 Exhaust Valve

Valve clearances are adjusted when necessary, such as when replacing valvetrain components or if there's noticeable noise. To check, listen to the engine; if noisy, adjustment is needed. This should be done with a cold engine. Remove the valve cover, position the number one piston at Top Dead Center (TDC), and adjust the number one cylinder's valves, starting with the intake valve clearance. Use a feeler gauge for correct thickness. After adjusting, tighten the locknut. Repeat for other valves. Rotate the crankshaft to adjust valves for other cylinders, then reinstall the valve cover.

Because of the toughness and the technical nature of the work and the use of tools and equipment in the process, an overhaul of the valves, the valve seats and the valve guides known as the valve job is best done by a professional. Home mechanics can unbolt and unscrew the head, prime wash and inspect the organ and re cable it for the dealer service department or an automotive machine shop where the actual service work is normally done. By performing the inspection, one is able to determine the health status of the head and the valvetrain part and what work has been done and what new parts will be required in case one has to deal with an automotive machine shop. The dealer service department popularly known as automotive machine shop will be responsible for the removal of valves and springs, reconditioning of valves and valve seats, reconditioning of valve guides, checks on and replacement of valve springs, rotators, spring retainers, and keepers if necessary, replacement of valve seals, reassembly of valves, ensuring that the correct installed heights are achieved. Also, the Cylinder head gasket surface will be machined if found to be warped. After the valve job has been well done by a professional, then the head will be as good as new. On its return to the engine, the head should be cleaned again prior to dressing the valves or finally re-fitting to the head where during the valve service or when the head is resurfaced there may still be metal particles and abrasive grit which should be removed using compressed air if available to blow through all oiling holes and passages.