e-proof, stay-up floats - setting float levels - ?????????

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(reference 74 Mk2) rebuilding the amal 932's today. I purchased new amal, e-proof, stay-up floats. the instructions that came with the floats are a bit confusing. the way i'm reading, for 1972-present, is to set the top surface of the float is parallel to the float bowl flange. to me, that seems a bit too high. the old white plastic floats have the level set at some pre-determined distance below the float bowl flange. looking for a little help for the float adjustment. so, anyone that installed e-proof, stay-up floats in your amal mark 1's, where was your initial float settings? old, white plastic dimension, or follow the new instructions, or ??? TIA....
 

L.A.B.

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The current Amal recommendation is to set the fuel level, not the float height.

http://amalcarb.co.uk/optimising-mark-1-concentric-fuel-levels
"The correct fuel level for all Mark 1 Concentric carburetters is 0.21" plus or minus 0.040" below the top edge of the float bowl. Thus when the needle valve is being held shut by the tangs of the float, the level of the fuel will be between 0.17" to 0.24" (4.33mm to 6.35mm) from the top of the bowl."

http://amalcarb.co.uk/rebuilding-mark-1-concentric-carburetter
Fuel Level
 
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The current Amal recommendation is to set the fuel level, not the float height.

http://amalcarb.co.uk/optimising-mark-1-concentric-fuel-levels
"The correct fuel level for all Mark 1 Concentric carburetters is 0.21" plus or minus 0.040" below the top edge of the float bowl. Thus when the needle valve is being held shut by the tangs of the float, the level of the fuel will be between 0.17" to 0.24" (4.33mm to 6.35mm) from the top of the bowl."

http://amalcarb.co.uk/rebuilding-mark-1-concentric-carburetter
Fuel Level
I understand about setting the fuel "level," but right now i'm looking for an "initial" setting on the "float" level. I've got to start some place - something in the ballpark. the first thing I need to do is get the engine started, then I can fine tune the actual fuel levels with something similar to the pic kommando posted.
 

jimbo

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I made a level check rig. It was hard to get a accurate level reading while running the vibrating bike.The way the fuel creeps up inside the plastic line was a problem . And the way the float bowl is shaped, caused the line to be further away than optimum .
 

L.A.B.

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I understand about setting the fuel "level," but right now i'm looking for an "initial" setting on the "float" level. I've got to start some place - something in the ballpark.
Initially, I'd suggest fitting them as supplied.
Assuming you have the alloy float needles then probably about where it's set in jimbo's linked post. Make sure the float pin is held down in the slot.
 
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Well if you just want to get the new stay ups in the "ballpark ", you could bend the ajustable tangs so that you have a match with where the original plastic ones sat. My new stay ups were sitting up too high right out of the box so I had to bend the tangs down a tad to lessen the rich condition that produced. Good luck.
 
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To dry set the stay up floats, set them parallel with and slightly proud of the top of the float bowls while holding down the tab. Then check the fuel level.
 

marshg246

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I understand about setting the fuel "level," but right now i'm looking for an "initial" setting on the "float" level. I've got to start some place - something in the ballpark. the first thing I need to do is get the engine started, then I can fine tune the actual fuel levels with something similar to the pic kommando posted.
Look here for how I do it when the carbs or bowls are off the bike - at the bottom you'll find exactly what you're asking for: https://www.gregmarsh.com/MC/afh.pdf I use it as a double-check, but in reality, it's just as good for a starting point.
 
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The link says he uses water to set the fuel level. If you're going to do the fuel level check as opposed to setting float level, I'm not sure using water is a good idea. It is denser than gasoline and, as a result, the float would close the needle valve at a lower liquid level than it would with gasoline. IOW, the "correct" fuel level setting using water could result in an excessive level with gasoline. I admit I haven't checked this so maybe the difference is not enough to matter though I would think it would be easily measurable. Maybe I'll check that out next week when I'm back home! :)

I wouldn't be surprised if there was a greater variation in fuel level from the stay-ups from float to float than there was with the plastic float. I suspect that is why Amal talks about fuel level now as opposed to float level as in the past. I suspect that they could confidently spec a float level to result in a particular fuel level with the plastic floats but there is too much variation in the stay-ups to do that.

Of course, when you factor in issues like ethanol/no ethanol and other modern differences in gasoline density, that could be an even better reason to spec fuel level as opposed to float level. But float level has always worked fine for me so I doubt I'll change! ;)
 

cliffa

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I made a level check rig. It was hard to get a accurate level reading while running the vibrating bike.The way the fuel creeps up inside the plastic line was a problem . And the way the float bowl is shaped, caused the line to be further away than optimum .
Me too. I have to say that of all the carbs I've worked on Amals have to be the hardest to set correctly (even with stay-ups). It's very important to keep the pivot pin in the correct position as the leverage of the float tries to push the pivot pin up too high in the bowl and that skews the level. I bought two of these and just left them on the bike joined by a piece of hose over the top of the carbs. That way I have an instant level indicator, a sediment trap, and carb drain in one. They also really help when you are tickling the carbs, as you can see the level coming up.



My rig...






Cheers,

cliffa.
 
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marshg246

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The link says he uses water to set the fuel level. If you're going to do the fuel level check as opposed to setting float level, I'm not sure using water is a good idea. It is denser than gasoline and, as a result, the float would close the needle valve at a lower liquid level than it would with gasoline. IOW, the "correct" fuel level setting using water could result in an excessive level with gasoline. I admit I haven't checked this so maybe the difference is not enough to matter though I would think it would be easily measurable. Maybe I'll check that out next week when I'm back home! :)

I wouldn't be surprised if there was a greater variation in fuel level from the stay-ups from float to float than there was with the plastic float. I suspect that is why Amal talks about fuel level now as opposed to float level as in the past. I suspect that they could confidently spec a float level to result in a particular fuel level with the plastic floats but there is too much variation in the stay-ups to do that.

Of course, when you factor in issues like ethanol/no ethanol and other modern differences in gasoline density, that could be an even better reason to spec fuel level as opposed to float level. But float level has always worked fine for me so I doubt I'll change! ;)
I've tried it with gas and water. The result is the same. The difference is the comfort while doing it.
 
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20170821_192605.jpg


This picture above shows exactly why measuring fuel height is misleading. If you look at where the top of the float is in the picture, you see that it's so high that it would have hit the underside of the carb body and NEVER get to the point where it would have shut the fuel off. It doesn't matter what the fuel height level shows in that tube, the float height needs to shut the fuel off much earlier because the float could never get this high when bolted inplace under the carb body... and with a float set that high, the fuel would NOT shut off.

The link Greg posted shows a float height that looks good... because it shuts the fuel off at a point where the float is pretty much as high as you can have the float be, without the float being so high that the underside of the carb body would prevent it from seating the needle to shut off the fuel... pictured below

 
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