Before you service or repair the valve, first take out the cylinder head. Use the Valve Spring Compressor Tool MD-998772A and the 6716A adapter to squish the valve springs, after that take out the valve retaining locks, valve spring retainers, valve seal rings and valve springs. Eliminate any burrs in the valve stem lock grooves before getting rid of the valves to make sure the valve guides are not harmed and be sure to identify the valves before reinstalling them. Before you install it, cover the valve stem with assembly lubricant and place it inside the cylinder. Regrinding the valves or seats means you need to verify the stem height; if it exceeds the cylinder head, you must replace the cylinder head. After you install new seals, continue with the valve springs and valve retainers. Use Valve Spring Compressor Tool MD-998772A and adaptor 6716A to compress the valve springs, put in the locks and release the tool. If valve grind is involved, find the spring height by measuring from the bottom of the seat hole in the cylinder head to the underside of the spring retainer or from the top of the spacer. Should the height of the spring be higher than 42.86 mm (1-11/16 inches), insert a 1.587 mm (1/16 inch) spacer in the head counterbore to make the spring height fall within the normal range of 41.27 to 42.86 mm (1-5/8 to 1-11/16 inches).