It is factory set, but on the spool where the dual throttle cables work the throttle is an adjustment, with a lock nut, where you can turn in and up the idle speed. I tweaked mine one turn in which is very slight. The hell of it is, it's not accessible once the tank is back in place. I just took a chance, thinking I can live with a little bit faster idle rather than stalling, just in case the new Air-Filter doesn't do the job. The service manual, did steer me to replacing the Air-Filter, but there is also an ISC-unit that is conceal in the neck of the frame. From what I can see the vac. hoses and wiring to it look and feel okay. So I am going to take a chance on that. I will try to remember to post as to how my approach works.
*My Road Liner is a 2006 F/I. but it only has about 16,000 miles on it. It's actually kind of a back up bike for me. I also have a Valkyrie, with 94,000 miles. The 2 combined have way less miles than I have on myself. Haha. I'm 75, and been riding nearly all my life, and thanking God I still can. Arthritis sure makes working on them tough though. Yup, I'm aware of the gas thing. Thanks.