GL1200 carb work

[Oldmannewwinger]

Hello, I appreciate all the careful answers to questions here. I have searched the site pretty well and still have a question.
Can someone explain the relationships between the vacuum operated needle jets, vs. main jet size vs. low rpm jet size vs. float level vs. idle screw adjustment? My 1985 Aspencade runs pretty well overall but smells a bit rich when idling and gets a little lower gas mileage than what I'm expecting. There is no hesitation ever and it has pretty good power through all RPMs. The idle is fairly consistent but slightly rough and maybe a little labored. It's all stock, but I'm considering installing smaller main jets. But maybe I should adjust the slider needle somehow?? The mixture screws are slightly less open than the manual calls for. The float levels are by the book.
BTW, I get the feeling that the 39 year old ignition system may not be optimally profiled. It has new coils, plugs and wires but I question the advance mechanism. As far as I know, it is all done by that 39 year old module with a vacuum line attached to it. Perhaps the mileage and performance would pick up if there was a way to optimize all that???
Thanks,

[Whiskerfish]

Really doubt that changing jets will resolve issues on a stock setup. Are thew carbs really really clean inside? What kind of fuel economy are you experiencing?

[robin1731]

Really doubt that changing jets will resolve issues on a stock setup. Are thew carbs really really clean inside? What kind of fuel economy are you experiencing?

This^^^^^^^^^^^^^^^^^^^

And they all run a little rich at idle. What do the plugs look like after idling 5 minutes or so? What do the plugs look like after cruising at 60mph for several miles and then shutting the engine off? Is the bottom of the plenum dry? Were the carbs rebuilt? If so were jets changed?

[Rat]

Anticipated mileage is low to mid 40s …

Gord(subject to wrist twist)Jones