E: Engine Amal 276-289 Leaking From Main Body

[CarlHungness]

After letting my twin sit for a few months I've experienced slight carb drip when going to start it, and in the past the drip has always stopped, I imagine after the washers get soaked. Now, (even though I cannot start the bike!) my front carb is leaking and it appears as though the leak is coming from the threads on the bottom of the main body. I just replaced all the washers, and still getting the leak. Looking for suggestions.

 

[Mike 40M]

It is always hard to find exactly where petrol leaks comes from. Very hard to see. So my guess is the most usual cause, a leaking float valve or maybe wrong petrol level. Only guessing but if leak stops with engine running, in my experience leaking float needle valve..

 

[greg brillus]

Fuel taps that leak internally will cause this as well........with the original side bowl carbys, the needle /seat in the bowl does not seal as well as more modern carb's........with a fuel tap that bypasses fuel even by the smallest amount will tend to make the high side carb drip........disconnect the fuel line off the tap and sit a small catch container under the tap overnight.......see how much fuel leaks past the tap......this is a very common problem both from original push/pull taps and more modern lever taps as well.......even new ones straight out of the box can leak.

 

[erik]

The old Amal carbs are well known for this problems! This one of the reasons many Vincent riders ( not collectors ) chose other carbs as replacement. Erik

 

[Vincent Brake]

in other words, bin it!!

 

[bmetcalf]

Or sell it on.

 

[vibrac]

You should check the fuel level dont forget the carb will rotate slightly on the inlet stub for small corrections in height
as for binning it I would rather have 5 old dripping carbs than a dreaded concentric

 

[Vincent Brake]

true..

 

[CarlHungness]

You should check the fuel level dont forget the carb will rotate slightly on the inlet stub for small corrections in height
as for binning it I would rather have 5 old dripping carbs than a dreaded concentric

I had concentrics for a few years and found pretty poor gas mileage. The original carbs came with the bike, were in a box, I put them on and have never had a problem since.

 

[greg brillus]

The driping carbs is quite normal to a point........generally leaking taps and/or incorrect float level (leaking float needle valve) all contribute.......I prefer the original 276/289 carbs anyday over any other carb on these bikes........they work well, look by far the best, as everthing including fuel lines and cables all fit as per the factory.......Most other carbs might work well, but anything other than a Mk 1 concentric has a large bowl and this makes the instalation ugly.......clashing with the rear barrel/head.......always a compromise.......On specials like Norvins, I tend to make my own manifolds so the carb possition is correct.