On the KZ1000/1100 versons of the BS34s there are two venting methods on the various versions. One system uses a tube with open vent located between the carb pairs... Looks similar to the system used on the VM carbs except both the 1&2 carbs have vent passageways that go up to the common "tee" and same for the 3&4. The other method has EACH carb venting independently with venting occuring via one of the two LARGE holes in the venturi edge. You can figure out which by blowing spray carb clean INTO the holes on the venturi edge and see which dribbles carb cleaner out the hole at the top of the bowl cavity.
If venting isn't happening as it should, the float system just won't work right. A vacuum or partial vacuum is set up in the bowl. Also, when checking float levels, make SURE that all air bubbles in the line are OUT... you can tap all you want but if you have an air bubble just up above where you can see in the clear hose, the only way to clear is to blow into the tube slightly and this will clear the air bubble.
