E: Engine Amal 276-289 Leaking From Main Body

[CarlHungness]

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.

I surely agree. I think my problem is simply worn out gaskets which I'll replace this week.

 

[oexing]

For the Horex 600 four valve I took one of the pre-monobloc Amals I got with the Argentinian HRD boxes 30 years ago. When you study the photo - yes , the angle of the carb and float is quite "wrong" but I don´t care as the bike goes quite well - and NO leaks from the Amal ! Sure, I had to fumble with the float needle for achieving a correct fuel level but this was no big deal at all. So yes, you can have them in no-drip style, but you may want to skip the fibre seal in the carb body bottom for some o-ring/spacer seal Dowty design. And on some there is an extra hole above the thread that might want some plug for sealing it.
Vic

 

[CarlHungness]

For the Horex 600 four valve I took one of the pre-monobloc Amals I got with the Argentinian HRD boxes 30 years ago. When you study the photo - yes , the angle of the carb and float is quite "wrong" but I don´t care as the bike goes quite well - and NO leaks from the Amal ! Sure, I had to fumble with the float needle for achieving a correct fuel level but this was no big deal at all. So yes, you can have them in no-drip style, but you may want to skip the fibre seal in the carb body bottom for some o-ring/spacer seal Dowty design. And on some there is an extra hole above the thread that might want some plug for sealing it.
Vic
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Looks like there is a washer and an o-ring in the photos. For the first time ever I took out the jet block
from the #1 carb and found the tiny hole (.0021") clogged and believe THAT was my starting problem..or
running problem..could not get it started. Will try to start soon as I get new washers. As far as fumbling with
the float needle, don't know how you modified it. There's a step in the needle for the clip, so am imagining
you may have machined a different step to achieve a different float height.

 

[oexing]

The tiny hole you found is the pilot jet, I guess, no wonder you had a hard time to start the thing. In my last photo above it is deep in the large countersunk hole and the jet gets fuel from the drilling from the bottom of the jet block, in my second photo right next to the 30 T . These pilot jets are known to be blocked with crud or corrosion from E 10 fuel. It is a mess to clean as you have to knock the jet block out of the body.
You may be right about the step on the float needle, in my case that was minimum 15 years ago - so I don´t remember. Some needles just got grooves and a clip shoved in to locate the float. No big deal anyway to do a mod with funny float chamber positions. You see the "downdraft " carb plus float chamber. Should not be allright like this with the float but no troubles from the angle as the float - ahh, floats and so got no weight on the needle - but looks weird . Did not care to find an angled chamber so far.
And yes, I went for a thin o-ring around a turned down fibre washer. The rubber is a better bet for sealing imperfections in the carb bottom.

Vic

 

[CarlHungness]

The tiny hole you found is the pilot jet, I guess, no wonder you had a hard time to start the thing. In my last photo above it is deep in the large countersunk hole and the jet gets fuel from the drilling from the bottom of the jet block, in my second photo right next to the 30 T . These pilot jets are known to be blocked with crud or corrosion from E 10 fuel. It is a mess to clean as you have to knock the jet block out of the body.
You may be right about the step on the float needle, in my case that was minimum 15 years ago - so I don´t remember. Some needles just got grooves and a clip shoved in to locate the float. No big deal anyway to do a mod with funny float chamber positions. You see the "downdraft " carb plus float chamber. Should not be allright like this with the float but no troubles from the angle as the float - ahh, floats and so got no weight on the needle - but looks weird . Did not care to find an angled chamber so far.
And yes, I went for a thin o-ring around a turned down fibre washer. The rubber is a better bet for sealing imperfections in the carb bottom.

Vic

I sure didn't think of the o-ring trick and applaud you for it. If someone asked me to 'turn down' one of the fibre washers, I'd have to stick it to a block and rub it on an abrasive. I thought the tiny hole was the pilot jet, but didn't want to embarrass myself by mis-identifying it. I've read of the pilot jet being clogged years back and have now experienced it. The front carb block fell out in my hands. To get the rear out, with the carb on the machine, I heated the carb body with my heat gun, wiggled the long jet, got it to come down about a sixteenth, and very carefully inserted a screwdriver and gently levered it another eighth inch or so, then wiggled it free. I scrubbed it with steel wool and was able to 'snap' it back in place with some force, not a lot, and it felt just fine as it went home. I haven't tried to start it yet as the fibre washers are leaking and waiting for replacements. I feel good my B-TH is showing bright sparks at very, very low RPM's, but am jealous of the electric chair sparks you are getting from your Ronco and Vertex. I took 'Calle's' advice and ordered some of the Nakaru coils which claim twice the voltage of the stock B-TH units. I'll first try the new B-TH's and then switch to the Nakaru's. I wrote to B-TH and asked why they don't use the Nakarus, and quite honestly they didn't really know about them and asked me to report back on their proficiency. I'm trusting the Nakaru advertising, along with Calle's experience, so possibly all of our members with B-TH's might be in for a happy surprise if they do work better. Wish I had known of the Nakarus previously.

 

[Mike 40M]

Was in urgent need for a new float bowl for a Norton WD16H. Unobtainable at that time. Except from Spares Company. Correct angle but slightly longer distance between carb body and bowl. Never had any leaks.
Contrary have a concentric Mk 1 on the Comet (with slightly drilled pilot jet). Works well.