Bing carb issue

[jimcarrr100rs]

George, thanks for the excellent explanation of the idle circuit.

[plusvee]

I am latching onto this thread so as not to open another one on this topic. My father (classic motorcycle collector for over 60 years) claims that Bing's are notorious for leaking gasoline, "it's one of those things in life" he says. I ask you though: do your Bing's leak a little gasoline too? I am not talking about gasoline leaking from the air screw (from where it would be normal in case), but from the float compartment cover and screws at the bottom. I am talking about cleaned and serviced carburetors (float check, needle replacement, new gaskets, etc.) Thank you.

p.s. I always close the fuel tap ten seconds before turning off the bike.

[schrader7032]

None of my Bings leak...all 5 of them!

[Seek]

Mine are not leaking, even with the tap open. Not that I let the tap open for longer periods, but just checking them, there seems to be no leakage.

But there always is some brownish sooth around the gaskets, so I guess it does leak a bit when in us.

[plusvee]

Thanks guys!!!
Basically the gaskets get soaked with gasoline (even though everything is screwed on tightly) and that's where the gasoline dripping starts. The gaskets are brand new and I can't figure out why this happens. I thank in advance anyone who can point me to a trick to solve the problem (if there is a trick). I was thinking of putting a couple of turns of Teflon thread (the kind used in plumbing) on the male threads, but I don't know if this kind of Teflon is compatible with gasoline. Is this a bad idea?

[Andrew]

Hi, Teflon won't work for long it breaks down by the gasoline , try looking carefully at the pot metal of the carb surface where the gasket sits and make sure it is perfectly smooth with no pitting, if it is then with a flat smooth file dress the surface down also the screw seat surface too and try again . I always tighten my screws really tight!

[vechorik1373]

The reason that the carbs are weeping gas around the float chamber lid, even with a new gasket, is that the two lid screws have been over tightened, and left that way for a long time. Pot metal is very soft. Overtime, both ears that the screws pass through will warp, and bend downward. Take the float lids off, carefully remove the gasket, and hold them upside down, and look at the ears in relation to the gasket surface. I'll bet you the outside edge of the ears are above the gasket surface. Easy to fix. Back the screws out of the lid far enough that they are below the surface. Take a small file, and work down the ear until it is even with the gasket surface. Then put them back on, and DON"T over tighten them. You will find that you fuel weep has stopped!

[plusvee]

Thank you guys!!! You are really very kind!
I will try with your valuable advice, I will update you if this fixes the issue.

[Slash2]

I’ll second Vech’s suggestion. This is very very common on these old carbs. Always remember that pot metal is soft and these old carb bodies need to be handled gently.

[schrader7032]

The gas level never gets to the top of the bowl in normal operation, so there's no reason for the screws to be that tight. The gasket is there for general sloppage if anything.