Carb sync question

[memper]

On my old suzuki bobber when I had to sync the carbs I had to adjust the low speed cable as well as the high speed cable. My '99 750 has but one screw for synching. How does this one screw adjusted at idle account for fuel usage at,say 1/2 throttle? Or have carbs come a long way since the 80's and "newer" carbs can account for all throttle positions with a single screw?

[Howie]

Synch at idle.  Check synch at oh, maybe 3-4K RPM.  If there is a noticeable difference (probably won't be) and idle mixture is equal on both carbs, compromise to best suite your needs.

[memper]

ok thanks. I dont understand how it works but I guess in time and with a bit of research....

[ducpainter]

ok thanks. I dont understand how it works but I guess in time and with a bit of research....

Your old bike probably didn't have vacuum operated carb slides.

On the Duc the slides are pretty much all the way down on the idle stop at idle so you're synching the throttle plate opening.

If there is a major difference at 3-4 K there is most likely a vacuum problem, or some issue with the cylinder pulling equal vacuum.

It's more like the SU setup on an old MG.