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amal float level fixture

Classic Norton Commando Motorcycles.

Re: amal float level fixture

Postby MikeG » Thu Apr 06, 2017 12:35 pm

Glad I took the time to read through this, as I'm about to make a similar test rig. In the same vein, my float bowls do not have drains but I like the idea of setting float level via the tube out the bottom of the bowl method (dynamic ?) rather than with the bowls off. Are the drain type vs non drain type bowl inter-changeable on a 930 carb?.............sorry to go off topic but
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Re: amal float level fixture

Postby L.A.B. » Thu Apr 06, 2017 1:42 pm

MikeG wrote:Are the drain type vs non drain type bowl inter-changeable on a 930 carb?.............


Yes.
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Re: amal float level fixture

Postby WZ507 » Mon Apr 17, 2017 6:44 am

WZ507 wrote:
gtiller wrote:I would suggest that with the volumes we are dealing with inside a floatbowl versus the size of the float, the difference between petrol and water would be absolutely negligible.

Sounds like a simple enough question to get a quantitative answer to since seattle##gs has made the test rig and can easily test gas, alcohol and water at a fixed float setting. The only comment I’d add is that carb bodies are typically contaminated with sufficient residue that water does not wet well on them (water can bead up and does not wet like gasoline on oily and contaminated surfaces), thus a drop of surfactant (dish soap) in the water is necessary to lower the surface tension of the water so it readily wets the gas line and carb components. Before running the experiment be sure to put a drop of water in the carb bowl to assure it wets, otherwise you are introducing another issue that you don’t want present in your experiment.


"Sleepless in Seattle" waiting for seattle##gs to complete the fuel level test with the 3 fluids. Did you or other contributors with test rigs ever try the 3 different fluids to quantify differences in fluid level at a fixed float setting? In the mean time perhaps I'll just think about Meg Ryan in Seattle.
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Re: amal float level fixture

Postby seattle##gs » Mon Apr 17, 2017 8:43 pm

I am going with the sure thing and continue to use gasolineand use a small fan to blow the fumes away from me. This method with the fan also works well if you are chopping onions. My eyes have become very sensitive to onion fumes and this solves the problems

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Re: amal float level fixture

Postby brxpb » Fri Apr 28, 2017 2:27 pm

I went as far as putting my bowls on the tilt in the vice when I set my level but for those who have used the piece of pipe method, how does the resulting float height compare to the figure that burlen/amal recommend?
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Re: amal float level fixture

Postby Mr. Rick » Fri Apr 28, 2017 8:13 pm

If by "pipe method" you mean attaching a pc of hose to the bowl drain plug and bending the hose up alongside the carb (which is what I do) the float level itself is irrelevant.
I just watch the fuel level. If it's even with the washer of the screw which holds the bowl up, you're good.
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Re: amal float level fixture

Postby brxpb » Sat Apr 29, 2017 2:21 am

Mr Rick, yes that's the method I meant, I was interested if any one had took a final measurement to see if those who used the amal spec float height were in the right ball park, there's lots written about the figure given by amal and whether or not it takes the tilt into account, why is it the same figure for Triumph etc,etc, I know it's irrelevent to the hose method but have any curious minds took a float measurement after setting up this way?
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Re: amal float level fixture

Postby DogT » Sat Apr 29, 2017 5:36 am

I kind of wonder if the float level isn't just a rough beginning and the final correct result is from the setting of the mixture screw?
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Re: amal float level fixture

Postby L.A.B. » Sat Apr 29, 2017 5:53 am

brxpb wrote:Mr Rick, yes that's the method I meant, I was interested if any one had took a final measurement to see if those who used the amal spec float height were in the right ball park, there's lots written about the figure given by amal and whether or not it takes the tilt into account, why is it the same figure for Triumph etc,etc, I know it's irrelevent to the hose method but have any curious minds took a float measurement after setting up this way?


I set the fuel levels at the mid position with the bowls horizontal. The Concentric Mk1 fuel level isn't super-critical as the standard setting is between 0.017" and 0.025". I doubt the slight tilt of the Commando's carbs alters the mixture by much, if at all.

http://amalcarb.co.uk/rebuilding-mark-1 ... arburetter
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Re: amal float level fixture

Postby Mr. Rick » Sat Apr 29, 2017 6:16 pm

brxbp: In reference to your question about " to see if those who used the amal spec float height "
The latest Amal instructions for this carb (link posted above by L.A.B.) do not even mention float height, as far as I can see. Which makes sense. Whatever the float might be doing, if the fuel level is not approx correct with the carbs fitted, you'd have a poor setup.
From the link:
" Because there have been changes to the float chamber since the Concentric carburetter was introduced, and because there is no way of knowing what alterations may have been made by a previous owner, measuring the fuel level is the best way of setting up the float chamber.

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 0.017" to 0.25" (4.33mm to 6.35mm) from the top of the bowl. "

Which is a long way of saying sorry, NO, I did not compare. And even if I had a float height spec, you couldn't pay me enough to pull the carbs off and check. That is one real PIA routine, even if I have figured out a way to get at those inside screws.
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Re: amal float level fixture

Postby kerinorton » Sun Apr 30, 2017 2:31 pm

Theoretically, the floats and bowls are symmetrical, so the fuel level in the centre should not change no matter what angle the bowl is. Therefore you might as well set the fuel heights with the bowls level, then you will get an accurate reading of the fuel level below the top of the bowl, as has been specified here.

After all, its the fuel level right in the middle where the jets are, that matters.

Dereck

ps as for the plus or minus allowance in level, I prefer to get them exactly the same. After all, you would not ride you bike with one foot peg higher than the other, or with bent handle bars would you.
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Re: amal float level fixture

Postby Steves » Sun Apr 30, 2017 2:45 pm

I see in latest newsletter from Andover Norton they have a little tool for checking float level, if I remember correctly about 8 quid.

I was pretty pleased with the balance and response from my Amals. I noticed that one carb primed (tickled) almost instantaneously. Decided the float height was probably too high. Finally got round to adjusting a week ago or so.

Now not so pleased as have introduced an occasional stutter or hesitation on throttle roll on. Probably play with the pilot adjusters see if I can cure it. Always something hey ho.

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Re: amal float level fixture

Postby Deets55 » Mon May 01, 2017 4:43 am

I find that setting the top edge of the float opposite the pin at 1mm below the edge of the bowl works well. When setting the fuel level measured at the center of the bowl, while the bowl is level could create a problem if it is set too high. The issue is, as I see it, is that once the carb is installed and at its 10 degree angle, the fuel level is the same as was set at the center of the bowl but could be above the gasket surface at the front of the carb, if set too high. Using the tube method connected to the drain plug you will see that 1mm at the front of the bowl translates to roughly 5-6 mm at the center of the bowl.
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Re: amal float level fixture

Postby seattle##gs » Wed May 03, 2017 7:42 pm

I've noticed that there is a big difference between setting the float level on the bench and checking it again immediately after a ride. Any one know what the level should be when pulling into the driveway and immediately shutting off the fuel? I read somewhere about drilling the float bowl for better flow.

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