Oh man, I am up a creek. I am installing the Tangerine cable system and one carb is fine, but after I installed the pulley, one carb is binding and will ALMOST return to idle, but it is binding on something. The carbs are rebuilt but I did not replace throttle shaft bearings. The carb works fine throughout it's range of motion except for the last 10 degrees where it should return to idle. If you let it snap shut, it shuts, but if you ease off, it sticks.

I have had this freaking carb and cable system apart and back together 5 times and don't know where to look. Carbs are Made in Spain 40 IDF

Stronger return spring?

I had something similar happen to one of my Dellorto carbs after a soak and rebuild. A few squirts of PB Blaster on the throttle shaft ends and springs freed it right up. In my case, I believe it was the springs. Even if it's your bearings, I would first give this a patient try hoping it will penetrate the bearing seals.

Had the identical situation on my car after carb rebuild. I sprayed a little liquid wrench on the shaft and worked it in and all is good. If I remember correctly I also loosened the nut on the throttle shaft and gently tapped it back and forth to find the sweet spot.

I have new sealed bearings from rebuilding my dells. Try everything else before jump down bearing replacement rabbit hole

I had to shim or remove shims my cam wheels to get things just right. Try to loosen the one on the carb that is sticking slightly to see if it helps, if it does you found your problem...

-Robert

I can think of a several possibilities.
1) the cable alignment into the pulley groove is important. Allowing the cable to drag on one side of the groove may add enough friction to overcome the springs, which are at their weakest when the throttle is closed. Thin washers on the cable support bolts are sometimes needed to finalize the alignment.
2) The could be a burr on the backside of the throttle stop plate where it was drilled for the pulley alignment pin.
3) Overtightening the nut on the throttle shaft may be enough to make the throttle shaft drag.

Ok, thank you guys. To finish this off, here is what was going on, and upon inspection I can see that this had been happening to a lesser extent:

one of the throttle stops was not tight enough on the throttle shaft, so the circular spring was pulling it out of alignment. Upon tightening the bolt at the end of the throttle shaft, it pushed the askew throttle stop against the carb. I eased off the nut, lubricated and it snaps right back to idle.

Regarding the Tangerine cable system, you HAVE to find a way to put the locking tabs back on the throttle shaft nut so you can leave that nut just a tad loose.

I use a dab of Blue loctite instead of the locking tabs.

When you rebuilt the carbs did you take the butterflies out completely?

If so you need to be VERY careful when you put the butterflies back into the shaft.
You need to put them in and install the screws loose.
Then you need to let the butterflies close and aligned them PERFECTLY with the bores.
Any misalignment will make them stick just before fully closed.
I let them "slap" closed a few times and look for light around the butterflies.

Then when you go to tighten the screws I use a block of wood to put up inside the throat to take the load off the shaft as I tighten the screws.

If you removed the screws without this backup block, you may have bent the shaft(s).
I did the first time I removed a set of butterflies.

Replacing the shafts is a PITA because I had to drill new holes for the accel pump cam. This requires a special tool from Weber to get it right.