I've just reassembled my carb with new fibre washers after a good clean. And it leaks, from here (red arrow):

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The level of the petrol in the float bowl is roughly half way up the bowl which seems about right and thats above the top level of that chromed union nut. I'm pretty sure I put the large fibre washer in there - is there anything wrong with just adding some thread sealant (Loctite 567) to the union nut thread?

Thanks
Murray

can't get the image to display in my post anymore :(

id make sure the bottom of the float needle is seating properly and make sure the top of the needle is located in the hole in the cap, i assume that bottom nut is tight. i cant remember but im sure if the floats halfway that seems a bit high??

barry

email (option): fullerbarry@hotmail.co.uk

A tip that I learnt recently yet can't remember where it came from is to soak all fibre washers in hot water for a while before using them.
They conform better if you do this.

Mark

email (option): pes.sales@btconnect.com

No amount of sealer will help if the float level is wrong or the needle valve is letting by. There is a bleed hole on the left side of the carb just above the guide notch for the jet block. I see you have a pre war carb but I can't see if you have the correct "Short" lower union nut. (It determines the float height). Never the less, they will often weep until the engine is running. Ron

email (option): ronpier@talk21.com

looks like the long nut

barry

email (option): fullerbarry@hotmail.co.uk

I found a post by Rik, 'Tuning the Amal 276' 15th May 2012 on this forum (if I make that a clickable link I get a forbidden! error)

where 'John of Australia' says the fuel level should be 'just below the top of the needle jet'. Thats above the top of the union nut so I'm going to assume I have a leak rather than excessive fuel height.

I'll do as Mark suggests and soak the fibre washer in hot water. Its a cheap one from an ebay assortment. Maybe I should use a more reputable supplier...

Cheers
Murray

It'll still leak out the bleed hole if the fuel level is too high or letting by the float needle. Ron

email (option): ronpier@talk21.com

Could be handy if you're pulling your carb apart.

https://pesltd.uk/?product=76-276

Mark

email (option): pes.sales@btconnect.com

Ron, as far as I can see, the Type 76 (I only have a stub fitting 76/11 here) does not have any bleed drilling in the jet block and the slot for the dowel is shorter, as per the Norton 276 type. For fuel to come out of the slot, it would have to pass between jet block and mixing chamber, having first passed the sealing washer.

Any excess fuel in a Type 76 would seem to exit into the main bore and either flood the engine or be spat out at the oil tank which is certainly what the Norton does.

This photo shows 76, 276R and 276 Norton type blocks. Only one has the drain hole to line up with an extended dowel slot.

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Ok Rik. I stand corrected. From memory I only have one bike with a 76 (My Velo MDD) and it's ages since I overhauled it. Will take a peek tomorrow. Also if I remember correctly, the 76 carb doesn't have the little brass plug at the opposite side to the idle screw, like the 276 has. Maybe that is a leak out place? Ron

email (option): ronpier@talk21.com

Ron, I haven't run a 76 so I don't know, but it is certainly so that the opposite to the pilot air screw is open. The drillings via the air screw are very small, but it may be so that it would drain there and that the Norton type with blanking plug suffered from not being able to do that.

Petrol is horribly migratory so it's difficult to tell, but a 76 should only overflow there or via the main bore. I think...(E.&O.E.)

If you get the chance to have a look, I'll be interested to learn what you find. Some of this really basic stuff has been lost with the passing of the generations.

I’ve gone through my bikes and have one 76 carb, two 75’s and one 74 and this spare 76 body. Without exception, they all have the open drilling opposite the pilot air screw.

Ron

email (option): ronpier@talk21.com