Terry, the easiest way is to find the special screw slot that will give you the correct level when screw is taken out. Note the rubber o ring on screw to prevent leakage after you put screw back.

Edit: This chaincase is on my 49 star twin... I'm assuming the 55 chaincases are the same...Edit again!: Perhaps not as Muskrat mentions... But you can still check that screw slot.
