2004-2009 Honda TRX450R/TRX450ER Service Manual, Page 113Get this manual
LUBRICATION SYSTEM (After '05) Install new snap ring onto the oil pump shaftInstall the balancer (page 16-8)
OIL PUMP DRIVEN GEAR
PRESSURE RELIEF VALVE
REMOVALINSPECTION
Remove the left crankcase cover (page 21-11)Remove the snap ring and pressure relief valve from the left crankcase cover