keihin cv34 carburetors

I’m looking for someone who knows these carbs. I keep have an issue that seems like the carbs are not breathing or venting, after a while i get a significant amount of air between the inlet T of the carb and the Petcock. What is going on? How are these carbs ment to vent air and keep fuel primed and flowing?

- new Petcock
- new fuel cap
-just disassembled the carbs and soaked in an ultrasound bath

Let me know if anyone knows how these thin
 Are ment to vent.
Thanks

wgcarbs.com/index.php/14-sample-data-articles/91-cv34

Nice article from wiredgeorge. Im not sure if you are having a venting issue. What makes you think that have a blocked vent, other than a bubble in the line? Describing your issue would be the best.

thanks for the article. The issues i am having is that after 20 minutes of riding, I am loosing prime in my fuel line to the carbs. It starts as a small air bubble for nearly goes completely dry while riding. I run a clear fuel line, no inline filter, from my Petcock to the inlet T on the carbs. 

Just to be sure... I know you replaced your fuel cap but did you try to leave the cap open when these symptoms developed? It could still be possible that the tank is not venting properly. Just a process of elimination.

To be completely honest I'm not sure what would cause this. Are there any kinks in your fuel line? Are your float bowls way out of spec? Are you using PRIME on the petcock?
Can you verify that the petcock is flowing well? If you haven't been using a filter, is there any blockage in your fuel tubes?

It feels like 20 minutes is way too long for these symptoms to develop if it was a severe venting issue. When I had a venting issue it took no more than 5 minutes to run the carb dry. I would just verify that fuel is flowing where they should first.

Hopefully someone more knowledgeable on this will pop in to help you.

Ya, my Petcock flows great on prime. There is no change when I pop the cap. I have no idea why this keeps happening. The photo shows fuel trying to flow.

Aw man that really sucks. My only suggestion at this point is make sure that fuel can free flow to each carb individually by taking out the float needles and spraying carb cleaner through the transfer tubes to make sure that nothing is blocking flow and to verify proper fuel level in the float bowls using the clear tube test. Sometimes without a fuel filter, rust or other gunk can get in the carb and block fuel getting past the float needle.

Other than an air bubble in the fuel line, what is the problem?  Are the float bowls running empty of fuel?  Those carbs have a drain feature, so it would be easy to crack the drains and see how much fuel comes out of each bowl when runing problems occur.  And I agree, do the clear tube test to check fuel level in the bowls.

Since you have pods, what rejetting have you done?  And did you verify that the pod filters are not blocking the vent on the inlet side of the carbs?  

I suspect, having experienced the same "issue" with an aftermarket vacuum petcock, that the internal diaphragm/closing spring is "stiffer" than the original Kawasaki unit, such that the manifold vacuum, at any throttle opening above idle, is insufficient to fully open the valve. 
I solved it by replacing the spring with one that is a little "less stiff".