Andover Fuel level tool 13.1688

p400

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Amal quote:
The new Amal 'Stay Up' float has stainless steel tangs which can be bent to alter the fuel level. The tangs can be easily adjusted, by clamping the float in a vice up to the spindle hooks and tapping the body of the float gently in the direction required until the required level is achieved.
 

marshg246

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Hi Greg,
What is the correct fuel level range of a new Premier Amal?
What is the correct method of bending the metal of a stay up float?
Thank you

View attachment 19181

Here's what Amal says: http://amalcarb.co.uk/optimising-mark-1-concentric-fuel-levels it's for MK1 and MK2 carbs.

The adjustment part is poorly worded but what you have in your picture is what they mean. The part where the float needle goes does not get bent. The arms between the pivot and float do. Tiny changes make a big difference. If you feel it bend, you went WAY to far! Actually, I put my bent index finger under the pivot point and my thumb on top and bend the float itself because I don't want a chance of deforming the pivot loops.
 

marshg246

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IMO, the "tool" is most useful which the carbs on the bike to see if they need work. Once I decide that they need work, I remove the bowl(s), use a single banjo with a piece of clear plastic and the tool installed with a rubber band to hold it the tube at the center of the bowl. Then holding the bowl level with a thumbnail holding the pivot pin down I run a trickle of water into the hose connected to the banjo and see the fuel level. It's quick and easy to do the adjustment and try again.

Before everyone starts:

Yes, gas and water have different densities - I've tested - no human can measure the difference for this test.
My wife died eight years ago and therefore I can use the kitchen sink for whatever I want. When she was alive I had to do it with a garden hose outside.
 

p400

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ElaborateFuelTool1.jpg
 
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Wonder why "fuel level" tools are now needed with the "upgrade" of stay-up floats and were not necessary with OEM floats. :rolleyes: Also, not sure using foam for float material can be called an "upgrade." Actually, I am sure... it can't. ;)
Mike, I'm with you! Marvel Schebler aircraft carburetors originally had soldered brass floats. Naturally, some of the 40+ year old floats cracked. So..... they replaced the perfectly good floats with ones made of foam. Guess what? The foam floats are nowhere near as reliable as the old brass floats. Don't be surprised when Amal switches away from foam floats in a decade.
A sinking float on a Norton is nowhere as thrilling as on a Cessna.
 
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"
Don't be surprised when Amal switches away from foam floats in a decade.
A sinking float on a Norton is nowhere as thrilling as on a Cessna."

I'll bet that's TRUE!!! :)
 

marshg246

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Good bit of talk about "foam floats". Where does that come from? Here's what Burlen (Amal) has to say about the StayUP floats: "
The AMAL Carburetter Company, (Burlen Fuel Systems Ltd) manufacturers of all genuine new AMAL Carburetters and spares Worldwide, have introduced a revolutionary new float for Mk1, Mk1.5 and Mk2 Concentric AMAL carburetters.

The new adjustable height StayUp float is resistant to modern ethanol based fuels and has a military spec closed cell construction, making it puncture proof. The ability to adjust the float arm allows for quick and easy minor alterations to float levels where required.

The material specified was used by the S.U Carburetter Company for military installations in the 1980s, where a guaranteed fail safe operation was critical. Due to the close link between S.U and AMAL today (both owned by Burlen Fuel Systems Ltd), the secret behind the material has been released and upgraded for the manufacture of this float, making it virtually unsinkable."
 

marshg246

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Anybody know what the tilt angle is for stock carbs on a Commando?
I've never measured it, but that tilt has caused quite a few posts about fuel levels in the past.

The pilot (idle) circuit is most affected by the fuel level. Since the pickup is at the rear of the carbs and since is works by vacuum and the vacuum is lower at idle, the level matters more at idle.

Since the carbs are tilted, a happy medium must be achieved. Too low and the fuel level at the rear is lower and requires more suction.

The fuel level is checked at the center of the bowl whether installed or not. Therefore, the fuel level is the same whether installed or not and should be in the range Amal specifies. IMO, the level needs to be the same for both carbs for good idle. Amal says: "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. "
 
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