72 Carb problem, continued

Ever since I got my 72 2+2 I've been fighting a miss that only happens on hard left corners, as on track or slalom...

After the carbs were rebuilt, and after they were refreshed with new floats and grosse jets, it's fine for a few thousand miles but then the problem comes back.

In addition to the missfire / lack of power, there is fairly substantial amount of gas leaking out and soaking the air filters.

to see where the gas is coming from, I put small hoses in the bowl vent holes (in he white circle on the top picture) and routed them in a bottle. After a few hard left turns, I had about 150ml of gas in the bottle. The air filters remained dry telling me the gas is coming out of the vent and not thru the needle in the carb throat. The vent is at the top of the fuel bowl, where the white arrow is pointing.

I hooked up a Gtech pro meter, I noted it takes about 0.6 G to get the missfire. That's higher than what I typically encounter on the streets making it harded to test....

I tried lowering the float to about 21mm vs the 16.5mm in the book, no change... Others have reported no problem slaloming at the normal setting anyway.

Fuel pressure is set at just under 2.5 psi, and the problem happened with a different pumps. There is no leak when the pump runs with the engine off.

I did find a defective float today, it can be seen in the picture below, one side half filled with gas...up to the white line... put an another one on, but that didn't help.

One thing I noticed, which may or may not be relevant, after shut down, there is a lot of vapor coming out of those bowl vents, causing a lot of bubling in the bottle where the vents where routed. May not be anything, but with the engine off and the pump off, where is all that air coming from?

On the plus side I'm getting good at removing those carbs... took me about an hour to remove both right carbs, reset the floats and putting them back in... once you figure that you can use the inside of the frame rail to guide the wrench when accessing those hidden nuts... it's not that bad...

Looking at the amount of gas coming out of the vent, plus the height where that vent is ( white arrow, bottom picture), it seems like it will take a lot of gas out of the bowl up the vent even if it doesn't all make it out. probably enough to cause the the fuel pick up to run dry and causing the missfire. ... does it mean that having a higher fuel level will help ?

Pascal Gademer
72 E-type 2+2