Return spring tension

[tongy66086]

Is there any adjustment to the throttle return spring?
I've noticed that my Aspencade does not return (very fast) to an idle when I let off the grip.
I have 3 complete sets of carbs, and notice that one of the others returns about like the ones on the bike, but the other set snaps back shut like I would think they should.
I would think your wrist would tire quickly as strong of a spring as was on that set, but I was thinking that as much as the Aspencade was built for comfort, maybe adjustable spring tension was something else built in.
If there is a way to adjust the tension, I'd like to tighten it up a little so it idles down a little faster than it does now.
Thank you to all for all the help I've gotten from this board.

[bs175dths]

There is a lot of linkage as well as a return spring on these carburetors. The linkage and the return spring do not have adjustments.
I have lubricated the linkage pivot points as well as the push/pull cables on my bike and the throttle closes nicely.
Keep in mind too, that each carburetor has a throttle piston which must rise and fall smoothly and without hesitation or the engines performance will suffer. They rise and fall due to the difference of atmospheric pressure between the air passing through the carburetor and the air stored in the top of the carburetor.
The throttle piston or the throttle piston cylinder must be clean to allow a smooth operation.
There may also be a small vacuum leak.

I suggest lubricating the linkage and the push/pull cables and see if that solves the problem.
Inspect for vacuum leaks at the intake-to-head (o ring), at the intake-to-carburetor (metal band), or at one of the many vacuum hoses under the carburetor assembly.

You may have to open the carburetors and inspect the throttle pistons and the throttle piston cylinders.

[Roleketu]

After this season's carb rebuild I also found the throttle doesn't "Snap" back very well. My solution was to make another backwards wind on the throttle spring on carb four. That's the left, rear carb where the throttle arm connects. When I let go of my throttle, it very much snaps back and decelerates. Further, I made sure the throttle cables weren't pinched causing the slow response.