Quote:

I actually went up a size on the main, lost the shim, & the idle improved with no other changes.



Well, let's think about that for a minute. Let's say for the sake of argument that the mains are contributing to the idle F/A. Wouldn't increasing the jet and removing the shim tend to cancel each other? I really think something else changed that caused your idle to respond differently. If the tuning is really close, you'll detect differences even due to humidity and barometric pressure. My bike always runs leaner (slight midrange flat spot) when the temperature falls below 50F or so, even after the motor fully warm. I'm not sure if this is the result of increased air density or reduced atomization (fuel condensation), but it's consistent. If my bike was setup leaner or richer, the effect would probably be masked.

'08 America Blue/White; Custom Headlamps, Custom Lowers, Clearview 20", Bafflectomy