[mobleydrew]

Since there is such a big difference in how the bike runs, from 1.75 to 2 turns out, perhaps the small rubber o-ring on the air screw is worn, allowing air to flow through the air screw adjusting orifice. Perhaps a new o-ring and closing off the orifice will correct this. Once I confirm this with a piece of tape, perhaps a dab of gasket sealer will seal it nicely, since the original plug for the hole is long gone.