Postwar flooding carbs

[KiwiJohn]

My 80 Plus looks great and runs well (though I have hardly ridden it much) however fuel pours from both carbs.

I have examined the float valves and they look fine, they just seem to be a marginal design with very little pressure to lift the brass cone against the seat.

So what can I do?  Is there a way to fit an 'O' ring or anything like that?  Is it a consequence of the high 'head' between the fuel in the tank and the low set carbs? If so can I reduce the fuel pressure somehow?

[davebarkshire]

I've never heard of unleaded fuel being a problem for carb leaks. I take it that the leak is due to flooding float bowls? If I had a leaking float chamber then my generic check list might go something like this...

1) Check that the bowls are not being filled with fine grit from the tank (* see note below)
2) Check that the floats are not punctured (and filling up with petrol)
3) Check that the float needles and seats make a good seal
4) Is the float attached to the needle in the correct position?
5) Check that the carbs are mounted vertically in both planes (** see note below)
6) Do you have the correct float chamber / carb combination? (**** see note below)
7) Check fuel level with a U tube (*** see note below)

* If there has been fine grit coming from the tank then it can accumulate in the hole at the bottom of the float chamber that the bottom of the float needle is located in. When this hole has grit inside it can stop the needle rod from moving freely and causes flooding.

** If the float chambers are of the wrong type (wrong angle) or if the carb is stub fitting then the float bowl may not be vertical which will cause flodding.

*** Not easy to do unless you make up some special fittings.

**** Amal float chambers came in several sizes.

If you find that the leak is not due to a flooding float chambers then you should get yourself a pair of carb gasket kits and make sure that you have the correct fibre washers etc. I don't know if there are incorrect pattern gasket kits doing the rounds but the thickness of the fibre washers that are used to fit the float chamber to the carb body can vary in thickness and this will affect the float level.

[KiwiJohn]

Thanks Dave, been through all those a few times now but some I will try again.

I managed to get the Amal booklet which was some help and the levels do seem to be right and I have inline filters too.