On my new G5, the NGK plug did reduce the frequency of dying at idle and it did increase the idle speed a bit but the computer seemed to keep on searching for the proper idle speed.
I reduced the idle speed because when riding in Phoenix the stop lights try to catch me forcing me to wait at the light. When the temperature is over 105F, a lot of idling can heat the engine up a lot.
I figured that if it was idling slower it wouldn't heat up as much.
I don't remember exactly what the mileage was but I know it was more than 300 miles when I did this.
Anyway, reducing the idling speed seems to have pleased the computer because although the speed does vary a bit it is not as noticeable as it
was.
If you decide to change the idle speed DO NOT touch the screws where the throttle cables fit. Those must be left as they are.
The real idle speed adjustment is the large brass screw that is located down in the top of the throttle body and can only be seen by looking down a large hole.
This screw is actually the idle air adjustment and screwing it in (clockwise) reduces the amount of air that passes thru the throttle body thus the engine speed will be reduced.
To increase the idle speed, screw the screw out (counterclockwise).
It only took about 3/16-1/4 of a turn in to reduce my bikes idle speed to a nice fairly steady Thump Thump Thump......