Suzuki 2 Strokes

What is the proper procedure for bleeding the oil pump? I had a dry oil line after a ride the other day so I pulled the pump off to check that it was sending oil to the dry line. Everything looked OK so I refilled the dry line and put it back together with the air box off so I could watch what's happening. I started it up, turned the oil pump to max and watched as air bubbles appeared not only in the line that was dry, but also in several others. I bled the pump again and got no air, just oil.

If the pump is properly bled where is the air coming from?