Hey Baz,
I'm looking at a stock airbox right now. If you are describing a large nipple-looking piece that aims forward, just above the carbs, it looks like the molded holder for the small "L" bracket that attaches to the frame and helps hold the airbox in place. It should NOT be a hole, unless someone MADE it into a hole.
From what you were first describing, it sounded like the hole on the left side of the airbox for Cali emissions. (I only say that since you said you have a 3-line tank) Otherwise, the small hole at the bottom of the airbox and on the right side goes to an "S" hose that relieves crankcase pressure (and some oil vapor) back into the airbox.
Try loading pics by clicking "advanced", then click the paper clip next to the b/w smiley face, and upload your image that way. It worked for me.
