Carb piston valve question

[zapper]

Hey all. 89" 1100. Rebuilt carbs, replaced float needles and seats, replaced gaskets and o-rings a few years ago before sitting idle afterwards and all rubber parts look good. Idles very smooth, no erratic operation or fuel leaks and seams the respond to throttle very well with no real problems to speak of.

Here's the question, when on the center stand with the airbox off and vacuum line plugged, only the #4 carb slide (piston needle) moves with throttle input.

All of them slide freely by hand with no sticking whatsoever so I'm at a loss.

Shouldn't all of them move at the same time?

When I rebuilt them (and cleaned), I did it twice because I didn't like it the first time with just a can of cleaner and compressed air. The second time I put all the parts in a can of parts cleaner for a few hours and blew everything out with compressed air again. Bench synched but didn't remove the A/F screws for the slow speed. But like I said, it idles smooth and seems to respond very quickly (almost instantly?) to throttle blips/input.

Are they fine and should I leave them alone or ?

Thanks in advance.

[GregS]

You should see all the slides lift when you open the throttle. All four should move close to the same amount in "sync". If only one were lifting the bike would be nearly unrideable, it would bog down horribly.
There's a vacuum passage that applies vacuum to the top chamber, above the diaphragm, to lift the slides. Check that the passage is clear.

[zapper]

Carb piston vavle question

Yeah, that's what I expected and understood to be normal as well.

The odd part is that it idles, runs and accellerates like an electric motor smooth. Definitely not accellerating as much as I expected, but everything else is so nice as to not indicate anything is wrong.

Guess I'll do another full tear down, clean and rebuild tomorrow and see what happens.