Oil Pump Overhaul: Inspection

Remove the screws from the pump housing, then separate the housing and the cover.
Check the inner-to-outer rotor radial clearance between the inner rotor (A) and the outer rotor (B). If the inner-to-outer rotor radial clearance exceeds the service limit, replace the oil pump.
Inner Rotor-to-Outer Rotor Radial

Clearance

Standard (New):

Service Limit: 0.06-0.16 mm (0.002-0.006 in)

0.20 mm (0.008 in)

Fig 1: Checking Inner-To-Outer Rotor Radial Clearance Between Inner Rotor And Outer Rotor
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Check the pump housing-to-rotor axial clearance between the rotors (A) and the pump housing (B). If the pump housing-to-rotor axial clearance exceeds the service limit, replace the oil pump.
Housing-to-Rotor Axial Clearance

Standard (New): 0.02-0.06 mm (0.001-0.002 in)

Service Limit: 0.15 mm (0.006 in)

Fig 2: Checking Pump Housing-To-Rotor Axial Clearance Between Rotors And Pump Housing
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Check the pump housing-to-outer rotor radial clearance between the outer rotor (A) and the pump housing (B). If the pump housing-to-outer rotor radial clearance exceeds the service limit, replace the oil pump.
Pump Housing-to-Outer Rotor Radial

Clearance

Standard (New): 0.100-0.175 mm (0.0039-0.0069 in)

Service Limit: 0.20 mm (0.008 in)

Fig 3: Checking Pump Housing-To-Outer Rotor Radial Clearance Between Outer Rotor And Pump Housing
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Inspect both rotors and the pump housing for scoring or other damage. Replace parts, if necessary.
Check that the oil pump turns freely.