gas "breathing" out of air tube...

Its a 1977 kz650.

I'm guessing its a stuck jet but I'm not sure.

Any ideas?

Would double-check hose connections.

Good Fortune!

Do you mean you've got fuel coming out your PCV breather tube? Can you tell whether one of the cylinders isn't firing? If a float is stuck, you could be pouring so much fuel into the cylinder that it's coming out the PCV. (If so, better change the oil!)

I'm a 2cyl guy, but would make sense that a stuck float in one of the vented float chambers could drip gas out the vent tube too.

Im not sure what the tube is called. There are 4 of them (black) that hang down from each carb.

When I say "breathing" its as if the carb dumps fuel, refills, then dumps it again, in other words its not just a solid stream of gas leaking out.

A stuck float sounds probable.

How do I disconnect the fuel tank from the carbs with out draining it?

I think I would like to drain the carbs and let some gum out sit in them for a couple days... A quick fix until fall when a full carb rebuild wont get in the way of riding

From your description, it sounds as if the Float Bowl's Needle Valve is sticking open then slowly closing while the Float Bowl overflows.

What's causing this cycle or pumping? Three guesses here:

1a - A sticking Needle Valve. Be prepared to remove the Needle Valve assembly and clean or replace the assembly. Estimated cost about $20.00 for Needle Valve assembly.
1b - Also, rinse out your tank, clean out your Petcock's Fuel Screen, add fresh gas and add a clear inline Fuel Filter between your Petcock and Carb's Fuel input connection.

2 - A partially flooded float in the corresponding carb. Be prepared to repair or replace the Float. Caution the Float pin is probably frozen in. Do not try to tap out the pin as this WILL cost you a new carb.

3 - A long shot... stuff from your Fuel Tank getting stuck in your Needle Valve. See 1b above.

This is your carb:



Best of success,
Bill

PS
Please add your year, model number and location for the best responses... and yes, it's considered real friendly too.
Bill

BTW, you will want to do the Fuel Service Level adjustment too. See following.



Best of success,
Bill

Not to hijack this thread, Bill, but can the float be tested? I'm having similar problems... I'm going to try replacing the float valve needle, but it looks and feels good to me. Carbs & gas are clean and free of debris. The floats... well... float. They, too, look good. But unfortunately I can't actually see them in operation. (I feel like a clear plastic float bowl cover would be easy to make with today's 3D imaging & printing devices and would market well!)

While bench testing the float level (carb fully assembled) the level settles right within spec. But give it another 10 minutes and the level creeps up and it overflows. I find that on the bike, the level creeps up faster than it burns off when running.

Don in CT
81 KZ440-D2

Im not sure what the tube is called. There are 4 of them (black) that hang down from each carb.

kz.chris, in case you didn't figure it out from the other posts, these are the float bowl drain hoses, which is also where you check your float level (assuming your carbs are similar to mine). As a couple of the images above illustrate, those hoses will spill gas if the float bowls overflow. If you open the drain screw with a clear hose attached (held upright close to the carb body), you can check the float level.

Don in CT
81 KZ440-D2

IMHO, Once you replace your Needle Valve assembly and add a good quality inline Fuel Filter then your clear plastic hose is as close to a clear plastic Float Bowl as is practical... but a clear Float Bowl is a really cool ideas.

If the Float is flooded you should hear the fuel inside when you shake it next to your ear... at least that`s what I could do went they were still a soldered brass assembly... way back in the brass-age. :lol: :lol: :lol:

PS

radon220 wrote:

I’m not sure what the tube is called. There are 4 of them (black) that hang down from each carb.

kz.chris, in case you didn't figure it out from the other posts, these are the float bowl drain hoses, which is also where you check your float level (assuming your carbs are similar to mine). As a couple of the images above illustrate, those hoses will spill gas if the float bowls overflow. If you open the drain screw with a clear hose attached (held upright close to the carb body), you can check the float level.

Don in CT
81 KZ440-D2

Just a note here. I don't know anything about the KZ440's... but on the KZ650-B1 the 4 Black Hoses are "Overflow Hoses" only and are NOT used to do the Fuel Service Level adjustment. :dry:

On the other hand, the brass Float Bowl "Drain Plug" must be removed and replaced by a homemade adapter with a clear plastic hose or the Kawasaki Tool, as in the diagram, in order to do the Fuel Service Level adjustment.

Again, I have no experience with the KZ440's so no comment from me on that model.

Best of success,
Bill