dont oil it mate, its highly polished stainless and should movefreely, once there is oil there it makes it sticky and attracts more oil/muck and makes it stickier.

have you got a k and N filter or piper x... these seem the worst as some oil from the elements is carried into the ar inlet of the engine , similarly if you are running higher boost with out a proper breather system, the oil mist from the breather is carried over into the inlet