if you didn't flush the system multiple times you likely didn't get the gas out of it.
pop the spark plug out and remove the banjo bolt from the top of the oil line feeding the head. if you can turn the engine over and get flow out of that oil line your pump is working. You oil pump runs off a gear on the clutch, it's possible that they are bound up, that one or more of the gears is stripped, or that they are interconnected in some other way.
While you're at it adjust your floats and replace your leaky needle valves that caused the leak in the first place.