Recently bought myself a nice 2003 Anniversary Sportster 883. It has developed a minor oil leak/ seepage between the front barrel and head. It does not use much oil or even drip on the driveway, but is a pain to keep the engine clean. I noticed a few other Sportsters of the same era and some have the same issue. Will a simple retorque of the headbolts help the problem, or is a top end gasket replacement necessary?