Why does 2007 Harley Davidson idle so low?

How do you know its low? Idle should be in the 950 to 1050 rpm range. I installed a MSD shift light. Its about the size of your index finger(tubelar in shape) I have a carberated softail so I opened the air/fuel to about two turns. Then I raised the idle to 950. I went back to the air/fuel mixture and found the "sweet" spot after going in and out a few times w/ the mixture screw. When the idle rose, I backed off on the idle screw to about 950 to 1000rpm. .