Squeaky carb noise...
 

Anyone ever have a noise coming from the carbs you would call a squeak, squeal, or squawk? Just finished building a fresh motor. Nicky P's & C's from LN, JE forged pistons, head went for complete rebuild. Installed brand new genuine Webers.

Motor fired and runs beautiful right off the bat. Trouble is that when the butterflies are closed there is a very loud squeak from one barrel when the throttle is closed and the piston is moving down. It is also a little hard to open that carb from closed. You can really feel the vac pulling on it. Once it is open just a touch, the noise goes away. I can quiet it with the idle stop screws but then the idle is 2K.

Anyone heard of this?

So I just swapped on another carb. Same noise. When I went to do a rebuild that intake valve was bent. Noise is totally in the carb. When I lift it off the noise goes away as soon as I lift off the base gasket.
What could the machine shop have changed on that cylinder? Doesn't make sense.