Amal stay up float question.

I'm getting ready to rebuild a set of Amals for my 850 & one for my BSA 441. A friend just got done doing two for his bike & said that he had to cut part of the top off of the stay up floats because he said they were "to tall & to bouiant" to achieve the correct fuel level & float hieght for his carbs. They are 30mm carbs bought new in 1986 & never used until now and he wanted to fit the new floats & aluminum float needles. He also said there are typo's in Amals directions, something about the float or fuel height Amal says to set at .021 but it should read .210 ??? Has anyone had this expireance? He said he has read a lot of posts saying people have had the same trouble but I couldn't find any... Also he said the guy from Coventry Spares told him there is a lot of fake Amal parts being sold that are way out of spec. His & my floats came from Old Britts so I just don't think they are fake.

gtsun said:

He also said there are typo's in Amals directions, something about the float or fuel height Amal says to set at .021 but it should read .210 ???

Click to expand...

The .021 error also appeared on one page of the Amal website, however I think it has been corrected = 0.21.

http://www.amalcarb.co.uk/TechnicalDetail.aspx?id=14

I recently did this on my Combat. I just scribed a line .21" down from the edge of each bowl and set each one in my vise with the top level . Then I rigged up a funnel and fuel hose to the bottom of the bowl and added gasoline until the level stopped rising. I had to bend the metal fork up slightly on each float but at .21" fuel level the tops of the floats were about parallel with the top of the bowl. This seemed to work out just fine for good running (even though I didn't bother to measure where the level is when the carbs are installed - You could find out by using a clear sight tube if you really needed to.) I got the stay-up float kits directly from Burlen. These come with new viton-tipped needles and bowl gaskets.

Shouldn't have to remove material from the top of the floats. This is a bit over the top - putting it kindly. Possibly the needle seats were way off and needed adjusting if it couldn't be done with just bending the forks.

The Amal kit instructions are a little heavy duty for something that is not that hard. It goes on and on about the history of where the needle seats were set over the years. In most cases no one knows what vintage their carbs are to use this info. I measured mine and both carbs were about the same and in the right ballpark for a later carb so I left them as is.

If you check the JBA site, there is some info there at the end about the Amal carbs on the Norton and the angle they sit at. He talks about raising the float above the bowl at the end of the article, but I haven't found that to be an issue for me. Actually I set my floats at 0.080 or 2mm below the back edge of the float bowl. I really don't know what the fuel level is. The Amal measurements didn't work for me, I couldn't even get the carbs to tickle and when I went back to my original settings, all is fine, even with the new stay up floats. Your mileage may vary.

Wouldn't it be nice if we all had the same measurements?

Dave

In the end Amals were meant to have best idle occur with pilot 1.5 turns out. Cdo's are not level nor still as a vice. Ballpark adequate recipe setting to run success can be judged by how close to 1.5 pilot turns out you find best idle. Its not that big a deal as pilot can compensate nicely, but this is a nit picking topic and float fuel level sets base line for the rest of the circuits. If not at 1.5 turns out only you will know you quit too soon.

batrider said:

I recently did this on my Combat. I just scribed a line .21" down from the edge of each bowl and set each one in my vise with the top level . Then I rigged up a funnel and fuel hose to the bottom of the bowl and added gasoline until the level stopped rising. I had to bend the metal fork up slightly on each float but at .21" fuel level the tops of the floats were about parallel with the top of the bowl.

Click to expand...

I did virtually the same thing, using a jug of fuel and the bowl in my vice. Ditto on having to bend the float tang up a bit. With the carbs in the bike I found that one of them would overflow when I blipped the throttle, from vibration. Had to progressively lower the float on that side until that stopped. So in the end the 2 carbs are different float levels.

Seems like it's not so straight forward sometimes...

would overflow when I blipped the throttle, from vibration. Had to progressively lower the float on that side until that stopped. So in the end the 2 carbs are different float levels.

Click to expand...

Sorry but makes me giggle on all he inventive measures to set floats when in practice... I had Trixie at 1.5 turns out till mysterious influence made the ticklers too low or the floats too high so flooded till needle seat set by guess/by golly down, a couple times mind you, till flooding stopped and pilot screws had to be back down over .5 turn too. Still don't know cause but too good now to take new chance on upsetting the sweetness.

I got anal, or is it amal and made up some float bowl drain plugs with nipples to accept and piece of clear hose, and then spent a hour or two setting up the levels to the mid point of the Amal dimensions. I then had the carbs responding to the 1.5 turns out on the pilots. I am not sure if this is the only set up responsible for my bike have a fuel injected style rock steady idle, but I can only say I smile every time I pull up and can just sit there without worrying about the engine stalling.

Cheers Richard

Unread postby stockie2 » Wed Aug 01, 2012 4:10 am
I got anal, or is it amal and made up some float bowl drain plugs with nipples to accept and piece of clear hose, and then spent a hour or two setting up the levels to the mid point of the Amal dimensions. I then had the carbs responding to the 1.5 turns out on the pilots. I am not sure if this is the only set up responsible for my bike have a fuel injected style rock steady idle, but I can only say I smile every time I pull up and can just sit there without worrying about the engine stalling.

Click to expand...

Very glad to hear your joy off a couple hours of quality anal fettering of Cdo Amals. I still don't understand the need of any sight tube though as I've gotten similar results just bumping the float level by feedback from the pilot turns in or out. If you found the 1.5 turn out gave middle of Amal designed optimal float level [which pleases me to know] then why bother viewing the level, why not just go by the pilot and tweak float till darn close to 1.5 turns. The monkey wrench in this is there are at least 4 different lengths and bluntness of pilot air screws, as revealed in current pilot turn survey. I found out myself there were two different profiles/lengths when I tried using thumb screw pilots I'd collected to find them too blunt or short to get anything but too rich idle so ended up putting the slotted kind back in for expected adjustment range again.

Interestingly at present my Trixie floats levels register on low side according to the less than 1 pilot turns out, starts idles and responds as I like my Combat to do, but I do hear rough sounds on let offs that hint at leanness yet the exhaust and plugs seem on the too sooty side. I remain confused on optimal tune up till more hours of you know what to find out.