It seems everyday there is someone asking why they have oil dripping out of their air cleaner.

There is a common misconception on what the proper oil level is on our Harley's. AND it is NOT helped by the confusing verbiage that HD uses in the manual AND on the dipstick.

Running the oil level so that it is halfway between the lower hash mark and the upper hash mark on the dip stick is NOT running the engine low on oil.

IT IS NOT LOW ON OIL UNLESS IT IS AT OR BELOW THE LOWER HASH MARK, at which point oil should be added to bring the oil level to halfway between the two hash marks.

The following is straight from the HD manual, and it is the same for the Twin Cams and the Sportster Evo motors-

"The correct oil level should register midway between the FULL and ADD marks on the dipstick.

If oil level is at or below the ADD mark, add only enough oil to bring the level to the middle of the two marks on the dipstick."

One of the confusing things is that Harley states that the correct (or full) level is "midway between the FULL and ADD marks on the dipstick."

While it is true if it is at or below the ADD mark, then some oil should be added. What is NOT true, is if it is at the FULL mark, it is full. If it is at the Full mark it is OVERFILLED.

Some will point out that the above applies to a cold oil check, and that is correct.

It is also correct that the manual states that you can fill the oil to the top mark on a hot oil check.

IT IS ALSO CORRECT that the manual states that when it is HOT, as long as it is above the lower mark you do NOT need to add any oil at all.

Experience has shown that the ideal level is midway between the two marks, hot or cold.

If you do that, and everything else is functioning properly (umbrella valves, rings, etc.) then you should not have any excessive blow-by causing oil accumulation below your air filter or along the side of the bike.