2004 John Deer Buck Utility ATV 500, 500EX and 500EXT Service Manual, Page 95Get this manual
Oil Pump Rotor and Inner Rotor Clearance mm (in) Service Limit Measure oil pump rotor thickness and oil pump rotor bore depthDifference between measurements should not exceed 0.2 mm (0.007 in)If so, replace oil pump rotors andor oil pump housing andor oil pump coverCheck the inside of oil pump housing for scoring or other damagesIf so, change the ring housingCheck rubber ring for damageChange if necessaryP0008441
0.25 mm (0.009 in
For installation, reverse the removal procedureApply engine oil on all parts before assemblingInstall pump housing with new rubber ringInstall pump outer rotorInstall oil pump shaft with needle pinInstall inner rotorRemove water pump and magneto coverRefer to MAGNETO SYSTEMUnscrew plug no21Remove compression spring no22, valve piston no23 and valve seat sleeve no24The regulator works when shiftingThe pressure should be between 600 kPa (87 PSI) and 800 kPa (116 PSI)