#2 Carb dumping fuel in air box

First post to the site but have used the site many times before on other kz builds. Here my issue, I have a 79 kz 650b3. The #2 carb is dumping fuel out the back of the #2 carb in to the air box... and possibly in the head too. I have replace the needle in 1 and 2 and it fixed 1 but 2 is worse now, instead of just running out the over flow its in my air box. Here is what I'm thinking. Over flow tube is clogged there for allowing the fuel to come out of carb instead of overflow and the seat is dirty or damaged since the needle is new.
I'm wondering also if my vaccume on the petcock could be bad? How do I test this and could this be happening and causing the over flow instead of the needle and seat?
Any other opinions would be great!

Crytsr1 wrote: I'm wondering also if my vacuum on the petcock could be bad? How do I test this and could this be happening and causing the over flow instead of the needle and seat?
Any other opinions would be great!

Hi Crytsr1,

The vacuum petcocks often go bad. You can check it by removing the fuel hose from the petcock when the bike is not running and the petcock is set to anyplace other than Prime. If the fuel flows the petcock is bad. A bad petcock will not cause the carb to overflow if the float valve is working properly.

Good Luck

Bill

Other possibilities might include:
Float installed upside down;
Float leaking;
Float tang maladjusted.

Good Fortune!

Check the petcock for a torn or damaged diaphragm. If gas can get past the diaphragm I believe it can then flow through the vacuum line that goes to the #2 carb. If that happens the float valve cannot stop the flow of unwanted fuel because it is not coming through the normal inlet. Ed

Good suggestion Ed! Hadn't considered that option.

Bill