nasty varnish

I believe these carbs have overflow circuits, where tubes connect to nipples from bottoms of float bowls and are routed to exit underneath the bike.

Where overflow circuit is clear and functioning correctly, the excess fuel getting past the float valve (for whatever reason) will escape through the overflow circuit, and not rise up into the carb throat.

Would assure overflow circuit is clear and unobstructed, which should resolve excess fuel rising up into the carb throat, but doesn't resolve the issue of excess fuel getting past the float valve in the first place.

Good Fortune!

I don't think these carbs have an overflow on them. The only thing in the bowl is the drain screw.
My brothers bike has the overflow, but his is an '81 750, mine is, well it seems to have parts from '82 and '83, been kind of a pain to get it going sometimes.
I'm still baffled by it, I guess I'll tinker around with it on friday when I have more time. Clean them out again, and set everything again. Compression check and the works I guess.

Looking at the Kawi parts diagrams, the stock carbs look to be Keihin CV34s. When you look at the side of the carbs can you see the word Keihin stamped into them? One of the letters is a star.

The overflow circuit on those is a brass tower that rises up from the float bowls. Did you see anything like that? There are not separate drain screws for it. There is just one place for a hose to connect at the bottom of the bowl.

Image shown below is for reference.

On some carbs, the hoses may serve double duty, provided there's a drain screw:
(1) As overflow when the drain screw is tight;
(2) As drain when the drain screw is loosened.

When doing the clear tube test to determine fuel level inside the float bowl on carbs with drain screw, the clear tube is connected to the drain nipple, and the drain screw is loosened.

If the drain screw isn't loosened, no fuel will enter the clear tube until the level inside the float bowl exceeds the overflow level, which overflow level is higher than the specified fuel level of 2~4mm below the gasket.

Where excess fuel is getting past the float valve for whatever reason, the excess fuel is supposed to escape through the overflow circuit (where an overflow circuit exists). But if an existing overflow circuit is obstructed so as to prevent escape of such excess fuel, the excess fuel then keeps rising on up into the carb to the carb throat, and flows both ways, back toward the air intake, and forward toward the engine combustion chamber.

Am wondering whether the clear tube test was correctly performed.

Am unfamilar with a carb that has an overflow but no drain screw, and don't know how the clear tube test could be performed. Because the clear tube test depends on drain screw (or drain plug).

The image below doesn't show a drain screw, which accords with the info posted by kz750saskatoon.

Good Fortune!

82KZ750 carb has drain screw per kawasaki.com.

There are NO brass towers in these bowls at all, not even a place for one to be placed in the bowl. There is ONLY ONE drain screw at the bottom of each bowl, and ONLY ONE nipple at the bottom of each bowl.
My carbs look identical to the ones pictured above in Patton's post, sans the brass tube at the bottom of the bowl. In the picture there is a tube sitting in the middle of the bowl, mine does NOT have that.

I am going to work on it again tomorrow, I will get some pictures of everything so we are all on the same page.

Seen172 wrote:

So I have everything all cleaned up again. Sound like it is running better now. I have been fighting cylinder 3, it doesn't like to fire all the time. I spray water on the head pipes and it takes a minute to evaporate, while the other three are instant. I have good spark, but noticed that fuel was sitting at the boot on my pod and the filter was soaked with fuel after it was warm and run around the block a few times. Could it be blowing back through the intake valve a little bit?

...filter was soaked with fuel after it was warm and run around the block a few times...

As suggested earlier in this thread, where fuel is noticed in the pod filters, fuel may have also entered the crankcase from the combustion chamber.

That raises a potential problem when carbs don't have an overflow circuit.
Same issue with Mikuni 29 mm smoothbores.
Must be very diligent to assure fuel level is being properly controlled by float valves and float mechanism.

Where excess fuel is for whatever reason getting past the float valve, without an overflow circuit to escape, such excess fuel rises up into the carb throat and flows backward toward the air intake, and also flows forward toward the engine and into the combustion chamber. And this potentially catastrophic condition may occur while riding.

Good reason to regularly sniff-test the crankcase oil to determine whether there is any fuel contamination. Results of which may be too horrible to imagine.

Good Fortune!