carb issue still unsolved????

Which bike are we talking about here ? Am thinking the 750/4. Does it have the Keihin CV34 carbs?

Strange that it does not leak out the overflow (brass nipple on the bottom of the bowl) If there is so much gas that it comes out through the pod filter then it really should come out the overflow also.

A few things to check. Like the guys above suggest check that the float is not hanging. Check that the float is not holed / filled with gas.
I would replace the float valve as the rubber tips do wear. A cheap fix. While you are at it soak a Q tip in carb cleaner and run it around the brass float valve seat. Unlike other carbs the seats on the Keihins are not removable or replaceable.
Check that brass overflow tube going straight down to the bottom of the floatbowl. I wonder if it is plugged Wouldnt be the main cause of the overflowing but again, overflowing gas should come out here first and it needs to be clear before you can do the fuel level test.

Like patton says check fuel level - attach a clear plastic tube to the overflow nipple and open the drain screw (again assuming CV34). Hold the plastic tube against the side of the carb and the level should come up to just a few mm below the joint between bowl and main body.
Good luck

Jordan,
Sorry this got so long. This is my first post in this forum, but I have been experiencing similar problems with my 1980 KZ1000 LTD. I had fuel flowing out of my overflow tube and the pod. There was a burr on the new inlet seat that I had just installed. I agree with what JR said above, but when I did my clear tube test, I had to attach the hose to the DRAIN HOLE in the carburetor bowl. It's my understanding the overflow tube will only be used if an overflow condition exists, so the drain hole is where your clear tube should be connected. I just used a small clear hose and screwed it into the hole where my drain plug goes. Then you can see how high the gas comes in the tube to see how high it is in the bowl. In your case this test will just show you that the bowl is overflowing and the gas will still come out of your pod.

I think the problem has to do with the Float, the float pin, the inlet seat, or the inlet needle valve. I don't see anything else that could be involved in the overflow condition.

Float - Remove the float from the bowl and put it in a bowl of gas to see if it floats and compare it's buoyancy to the known good floats.

Float Pin - With the float installed in the carburetor, make sure the float moves freely up and down like the others.

Inlet seat - After using a cotton swab as JR suggested, get a magnifying glass and plenty of light so you can see the seat. This is how I found a burr on my inlet seat. My seats are removeable so I was able to replace my seat to fix the problem.

Inlet needle valve - Remove the valve and with your magnifying glass, inspect the tip. If it is metal all the way to the tip you can clean it using a piece of paper as sand paper. Just rotate the valve rubbing the end of it on the paper between your fingers. This method polished mine up fine. If the tip is rubber and marked up, you will probably have to replace it. Also check the small shaft to see that it springs in and out just and feels just like the others that are working.

*** I also read that you held the carburetors up so the floats hung down and they all looked about the same. That is the position the floats are in when the bowls are empty. You need to do the opposite...... Hold the carburetors upside down so the floats are hanging in the closed position (up) as if the bowls were full of gas and pushing them up. See if they all look the same that way. Somewhere you might be able to find a measurement to tell you how many millimeters there should be from the bottom of the float to the surface where the bowl bolts up. That measurment would get you close, but I've read that the clear tube test is the only sure way to know the fuel bowl level.

Here's what I would to next:
Swap the needle and float and float pin with another carburetor and see if the problem moves to that other carburetor. When I did this, I moved the needle and seat to one carburetor, and the float to another. My overflow condition moved to the caburetor where I had moved my needle and seat. Keep track so you can put everything back to the original position once you have found the problem.

I am by no means an expert on this, but I am in the middle of the same sort of problem. I still have other issues before it will be running just right, but I hope this helps you get past this overflow problem.

Good Luck,
Scott

superduty said

"It's my understanding the overflow tube will only be used if an overflow condition exists, so the drain hole is where your clear tube should be connected."


I asked jordan which bike and which carbs because the standard Keihin CV34's which came on the 81 and 82 750/4s are a bit odd in that the overflow nipple and drain nipple are one and the same

Jordan, If your carbs are soe=mething else then please disregard my post.

Take a look at the attached pic which shows a CV34 with K&N pod and clear plastic tube attached. If you look close you might be able to see the fuel level in the tube.

Good luck

yes, those are the style carbs i have on my 750/4. I will pull them off once again and try all the valuable information posted (thanks superduty and JR). As said before, when I adjusted the float quite a bit it no longer leaked from carb 4. Just today I figured I would turn the gas on and sit and watch what happens:unsure: . After a while gas began leaking out of carb 3!!! Not nearly as bad but a steady drip from the pod . WTF!!! i will try your suggestions though and see where I am at then.

The gas level is overwhelming the float seat/needle and then filling the bowl. Some gas will come up through the top of the float chamber via the needle jet opening in the bottom of the venturi and then out your pod. It will also be flowing down into your combustion chamber. Figure out why the problem is occurring and then change the oil as it is gas-fouled for sure. OK... does this problem happen when the bike is running or parked? The carbs in question are Keihin CV34 and they can have plastic tees between each carb pair (1 & 2 and 3 & 4) OR vent through the big holes on the edge of the venturi. If you have vent tees between the carb pair centers, they must not be obstructed or a vacuum will set up in the float bowl and the floats won't work as they should... read overflow or no gas will come in.

If the vents are not obstructed, the next thing to do is clean the float seats using some brass cleaning stuff and a q-tip and replace the float needles with the correct type which will have rubber clad tips. Then set the float levels using the service fuel level method. That stuff will help but if the carbs are leaking when the bike is just sitting, then fix your petcock which is likely flowing gas. It will be either the vacuum hose going to the petcock being compromised or the petcock diaphragm. If it happens when the bike is running after replacing the float needles, cleaning the seats and setting the fuel level, then the cylinder is not firing all the time and allowing gas to just flow without being burnt. That will likely be an ignition problem since gas flow doesn't seem to be the issue.

this problem occurs when the bike is parked, but continues to occur while it is running. I removed the vacuum lines and capped what is necessary. with this information is it easier for you to diagnose the problem wiredgeorge?