just for info as it has come up - the oiling of a filter is to catch the really fine particles that ordinarily would pass through the filter, hence the requirement to clean and re oil periodically - it is only to be a very light oiling, the filter shouldn't be dripping in the stuff, on the pipercross ones the only way you can tell its been oiled is it changes colour slightly as I use the blue putoline filter oil but after a day on the track particularly in dry conditions it is covered in dust and light blue no longer