1979 GS1000 Carb Synchronize Help Please

[Eric B]

I did not realize it was ok for the two outside carbs to be 2 cm higher than the inside carbs. I read everything I could find on how to synchronize these carbs and decided to "tweak" them. Unfortunately, I did not keep track of the starting point. Problem is that #1, #2, and #4 are now higher than #3.
Any attempt to bring #1, #2, and #4 down raises the idle. Turning the idle adjustment screw doesnt help (because its controlled by #3) and adjusting the throttle cable only made a slight improvement. The only way to lower the idle is to adjust #3 carb which also lowers the reading on #3. It's a vicious circle. I can synch the carbs at 2000 rpm but then there is no way to bring the idle back down. Is there any logical explanation for this? I tried swapping hoses and nozzles on the carbtune to see if something was wrong with the synchronizer. Thank you for your help.

Can't upload photos. Current readings on my Carbtune are as follows. The manual says to synchronize at 1500 rpm.
#1=28
#2=24
#3=20
#4=28

[Nessism]

The adjuster for #3 is topped out. You need to make sure all the adjusters are in the middle of their range of adjustment before syncing.

[Big T]

And, you do have the vacuum port on carb #3 closed off?

[Eric B]

Big T - is that a vacuum line? Yes that could explain it. I thought it was a vent. There is one at #2 and #4 also. Should they all be plugged or just the #3?

[Rich82GS750TZ]

[Eric B]

Rich - Thanks!

[Rich82GS750TZ]

I can’t take credit for the pic. I just keep it in my Imgur album along with a similar pic of CV carbs to post whenever these questions come up about what hoses go where.

[Eric B]

Thanks Ed, Big T and Rich!!!! Carb synch was a breeze today. And I learned a lot.

[salty_monk]

Nice to have a success story! The vacuum port being open will definitely screw things up. Best to do it with a fan running in front too so it doesn't overheat