I recently fitted an oil pressure gauge on my 72 Commando, connected it to the left hand rocker box fitting. The oil pressure is 10-15 psi, and it does not change much from cold to warm or with varying rpm`s. The bike suffers from wet sumping, so I am quite sure the oil pump is worn. Assuming the gauge is OK, is there anything I can do to the oil pump to make it seal better (besides changing it out)? I have heard about "lapping" the pump, what does that mean ?