Withdrawal
Loosen the oil pump drive gear pulley bolts after removing the oil sump.
Bend back the retaining plates and remove the oil pump.
If necessary, remove the adjusting plates.
Installation
Replace pressure reducing valve o-ring.
Install the oil pump by placing the oil pump drive chain tension adjusting plates between its housing and the cylinder block; while the holes for the passage of oil in the plates must coincide with the hole in the cylinder block.
Install the oil pump drive pulley and chain and tighten the pulley mounting bolts.
Check the tension of the oil pump drive chain, which should flex when pressed with your thumb.
If necessary, adjust the tension of the oil pump drive chain by selecting the thickness of the adjusting plates.