I had to do it, I really wanted to try out my premix idea so I thought I'd give it a shot first. I realized the previous owner had installed an improperly fitting oil inlet line, so I replaced that with a clear oil line and while doing that I also checked the port on the oil pump and the port had oil in it so I'm assuming the oil pump was full. I then installed the new clear oil inlet line and left the old oil outlet line alone. The oil outlet line obviously had air bubbles in it since I did not attempt to do anything with it. So I then made sure I had premix in the gas tank and fired the moped up and held the oil control lever open while it was idling. After a second or two or holding the oil control lever open, there were no more bubbles in the oil outlet line (and none in the inlet line, although the inlet line never had any anyways). I'm going to be running premix in the moped for a while anyways and will periodically check the lines, but I think the oil injection system is essentially bled now since I don't visually see any bubbles in either the oil inlet or outlet lines. If I did it the way the manual states, I find that filling the oil outlet line with an oil squirt can is a tad more cumbersome than I like due to the limited space in that area. And the manual obviously tells Urban Express owners to do that because if they just run pure gasoline in the gas tank but have air bubbles in the oil lines, they can starve the engine of oil for sure. So I'm not recommending my premix method obviously, but as of now it at least seems to be working fine. I'll have to check it for a while to see if any new air bubbles form or anything, but I definitely prefer doing it this way over the manual's method.