Carburetor floats - checking for leaks
Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models
Most of the time, you can simply shake the float next to your ear and listen for any fluid moving around inside the float. An alternative technique was contributed by John Prusnek on the Yahoo! Loopframe_Guzzi news group. In John's own words:
Another way to test floats for leaks is to put them in the freezer overnight, then submerge them in a cup of hot water, look for bubbles as the air inside expands.