VM24 and VM26 float bowl leaks HELP!

Hey all, I'm loosing my mind here. I'm on my second rack of carbs (VM24 and VM 26) and I cannot get a seal on my float bowls. This a very long story but I'll keep it to the float bowl gaskets. I'm on my second set for the VM26, the second being the thicker 1mm and they still leak. When I say leak I mean nearly pour out. In process of replacing O-rings on the bowl cross feeds on my vm24 I got a bowl leaks, replaced gaskets, still leaked. Grabbed a set of 26's same thing, but those may have leaked before. Replaced those bowl gaskets with the thicker gaskets and same thing. What am I doing wrong? I know that they are old, but for sure the bowls didn't leak on 24's prior. I have been bottle feeding them to wet set floats and they're a little low but they leak. I have squeezed the bottle to hurry the bowl fill process. I'm considering RTVing the gaskets and letting them set up and then installing but I surely do not want RTV in the carb bodies. 

Do not use rtv.
It will swell in the bowls and jam the floats.
You should check the carb bodies and bowls for warping at the corners.
The warping can be made worse by using gaskets that are too thick..
The bowls can be lapped on a flat surface with wet'n'dry etc.
The flat surface usually needs a slot or hole in it to allow the brass overflow tube to clear.
 

If you are using pumper carbs, the size of the pump nozzle O-rings is critical.  They must stick up above the height of the gasket, which is pretty thick for such a small size O-ring.   I bought a couple different sizes before finding some that were suitable.  You can tell this is a problem if you have the carbs on the bench, full of fuel, and then manually activate the pump.   Also, there are some real crap gaskets out in the marketplace.  The proper gaskets are about 1.5 mm thick, but many guys use 1 mm thick material, which is questionable.  

Another thing to check is for cracks in the float bowl overflow tubes.  And of course, check fuel level.  VM carbs are hard to get a good fuel level on them; they typically come in with a high fuel level even though the float height is correct.  It might have to do with the floats getting heavy from soaking up fuel for 40+ years.  I'm not sure, I just know that I've struggled on some sets.

Firstly set the fuel level using the wet method. Measuring the height with carbs upside down will only get you close and doesn't take into account the differing bouancy between floats.
Secondly ensure floats are straight to the bowl edges and are not catching on the bowl side causing over fueling.
Thirdly ensure bowl surface is flat and true.
Lastly what material gaskets are you using? The card type often need to be left for a day or two to absorb vapour and swell before they seal  properly. 

Nessism, the orings you're talking about (i think) are by no means higher than the gaskets. If memory serves, they're not much higher than the metal surface. To be clear, this is the tiny oring that has a tiny wire hold down on the gasket surface? If this is the case, I'm going back to the VM24's. GASKETS- where are these 1.5mm gaskets at? Fattest I found were 1mm, the rest were thinner? O-RINGS, can you point me in that direction as well, I might as well finish the 26's too, but later as bowl gaskets are needed for both. I'm sure I smashed the crap out of the one in my 24's out of trying to eliminate the leaks, same for the VM26's.... thank you!! 

Nessism post=878102If you are using pumper carbs, the size of the pump nozzle O-rings is critical. They must stick up above the height of the gasket, which is a pretty thick O-ring for such a small size O-ring. I bought a couple different sizes before finding some that were suitable. You can tell this is a problem if you have the carbs on the bench, full of fuel, and then manually activate the pump. Also, there are some real crap gaskets out in the marketplace. The proper gaskets are about 1.5 mm thick, but many guys use 1 mm thick material, which is questionable.   Another thing to check is for cracks in the float bowl overflow tubes. And of course, check fuel level. VM carbs are hard to get a good fuel level on them; they typically come in with a high fuel level even though the float height is correct. It might have to do with the floats getting heavy from soaking up fuel for 40+ years. I'm not sure, I just know that I've struggled on some   Nessism, the orings you're talking about (i think) are by no means higher than the gaskets. If memory serves, they're not much higher than the metal surface. To be clear, this is the tiny oring that has a tiny wire hold down on the gasket surface? If this is the case, I'm going back to the VM24's. GASKETS- where are these 1.5mm gaskets at? Fattest I found were 1mm, the rest were thinner? O-RINGS, can you point me in that direction as well, I might as well finish the 26's too, but later as bowl gaskets are needed for both. I'm sure I smashed the crap out of the one in my 24's out of trying to eliminate the leaks, same for the VM26's.... thank you!!   

Warren3200gt post=878104

Firstly set the fuel level using the wet method. Measuring the height with carbs upside down will only get you close and doesn't take into account the differing bouancy between floats.

Secondly ensure floats are straight to the bowl edges and are not catching on the bowl side causing over fueling.

Thirdly ensure bowl surface is flat and true.

Lastly what material gaskets are you using? The card type often need to be left for a day or two to absorb vapour and swell before they seal properly. 

 

I had no idea that they needed time to swell

 

 

Gaskets don't need time to swell.  Some will swell, which affords a long-lasting seal, but they also should seal from t=0.  

Nessism, Gaskets don't need time to swell.  Some will swell, which affords a long-lasting seal, but they also should seal from t=0.  

​​​​​​Think it depends on which make of gaskets are used Nessism. 
I always drain the bowls and run dry bikes I winter layup. By the time the bowls are refilled in the spring the gaskets have had a chance to dry out. They will weep from the bowl seat when the bike is on the side stand for a day or two until the gaskets re swell and from then on they are fine until the next layup. 

As already pointed out you need to correctly set the fuel level in the bowl.  You also need to ensure there is nothing holding the float valves open.  Lastly, check your floats to ensure they aren't rubbing on the side of the bowl.  

They're leaking from the bowl seal not the overflow tube? 

Looking back through my records suggests the proper O-rings for the pump nozzles are either 2.0 x 3.0 mm (thickness x ID), or 1.9 x 2.8 mm.  I suspect both would work.

How many bowls are leaking?  I've never had a bowl leak in all the carbs I've done, but your mileage may vary, of course.