1998-2001 Honda Fourtrax Foreman TRX450S, TRX450ES Factory Service Manual, Page 85Get this manual
LU BRICATtON SYSTEM Remove the snap ring, washer and oil pump shaftMa,rk the rotors which si de is up, s'o they can be reinstalled th e: same wayDisassemble the oi pumpPUMP SHAFT
SNAP RING Thorougl)ly clean all the compon entsInsta ll the outer and Inner rotors into the pump body and temporari ly insert the oil pump shaftMeasure the pump body clearance SERVICE LIMIT: 0.25 mm (0.010 in)