At what stage di I adjust the air screws

[Guest]

Hi all. Just in the middle of doing my first carb clean-up and cycle o-ring replacement on an 81 GS1000G. I am going to start reassembling tomorrow morning. I've done a lot of research while the carbs were soaking and I am now confident this rebuild should go pretty smooth. However, I still have a gray area concerning the air screws. Again, after researching, my plan is to back these out from being "lightly seated" 2 full turns.I came up with this number because on several posts i found the numbers 1.5 and 2.5 turns so I thought I would just split the difference. Please,please feel free to correct me if this is not right. I guess my question is this. After bench syncing, and reinstalling carbs on the motorcycle, start and warm-up, is it at that time that I adjust these air screws to get the smoothest idle possible? . I have a Morgan Carbtune on the way for the final and proper sync but these air screws are not part of that procedure. Does this sound like I am on the right track here??

[Nessism]

I'd go 2.5 turns. Regarding the proper order, you should be fine. As long as the screws are within about .5 turn of each other you are fine. You can always play with them before and after vacuum sync and see if there is any difference.

[crazy canuck]

I'd go 2.5 turns. Regarding the proper order, you should be fine. As long as the screws are within about .5 turn of each other you are fine. You can always play with them before and after vacuum sync and see if there is any difference.

Thank you Nessim. And these are to be adjusted for smoothest idle possible??

[Nessism]

Yea, the idea is to tweak the screws and pay attention to any idle speed changes. You want the highest idle speed. In my experience there is not a whole lot of change though unless things are way off.

[Steve]

"Highest idle speed" is always a good ideal, but you may find a rather wide range of screw adjustment that makes no difference in engine speed. In that case, turn them IN slowly, listening for a decrease in engine speed, then back them out about 1/8 turn to where it idles better.

Everybody has their favorite starting point, I use three full turns. That way, I know it's already plenty rich, so it will start easily and I only have to turn them IN to where it stumbles slightly.

It also helps to know that you DON'T have "air screws" on your carbs.
You have "idle mixture adjustment" screws.

.

[OldVet66]

Some of these adjustments might not make more than a fraction of a needle width difference on the tach, for highest RPM, but overall they will make a huge difference in the way it runs. When you are dialed in there is plenty of low end power easing off the line without the tendency to want to slip the clutch to keep from stalling, good idle, good low speed manners as well as smooth acceleration up through Red Line.