2004 John Deer Buck Utility ATV 500, 500EX and 500EXT Service Manual, Page 98Get this manual
if necessaryCheck if the valve cover gasket is brittle, hard or damagedReplace if necessary For installation, reverse the removal procedure
Always disconnect the negative wire from the battery before working the engineEven if the removal of many parts is not necessary to reach another part, it is recommended to remove these parts in order to check themWhen disassembling parts that are duplicated in the engine, (e.g valves, springs, etc, it is strongly recommended to note their position (PTO, MAG side) and to keep the parts of the same assembly as "group"If you find defective component, it will be much easier to find the cause of the failure among its group of parts (e.g you found worn valve guideA bent spring could be the cause; it will be easy to know which one of the springs is the cause and to replace it if you grouped the parts of the same assembly at disassembly)Besides, since used parts have matched together during the engine operation, they will keep their matched fit when you reassemble them together within their "group"When the repair is done, test drive to confirm all is working wellIf the test drive is good, perform change of engine oil to catch all metal chips or other debris in the engine coming from the repair