The Bing Dual-Independent "Alcohol-proof" Float Kit
>>>A Bing, NOT BMW product!
Copyright, 2014, R. Fleischer
The MAIN advantage of these kits is that you do not ever (probably) have to replace the
floats. That does NOT apply to the float needles, of which there were two basic types.
The VITON tipped ones have the same easy-to-lose fine wire clip as on the stock
carburetors. That clip insures positive float needle operation.
If the original floats (which DO AGE) are really bad, and/or the float needle is bad, things will certainly improve with PROPER installation of these PRICEY kits! Installation is, however, somewhat tricky.
IN MY OPINION, installation of these kits when the old parts were worn, often considerably, is the HONEST & TRUE reason that SOME find improvements with fuel mileage.
Adjustment of these dual-independent float kits is more involved than with the stock floats. These kits can have nasty problems, so read all of this article.
Introduction to these kits:
(I will get much deeper into them after this section)
NOTE:The old method of turning the carburetor upside down for adjusting the float level is no longer used for the STOCK one piece white floats...but it IS for these Bing dual independent floats! At least per Bing's instruction sheets. However, by using one's finger, carefully, one can adjust the float bridge of these Bing kits, while the carburetors are on the bike...and Bing's latest sheets reflect both methods of adjustment. Note that adjusting even the stock floats using the upside-down method is somewhat tricky, particularly with the sprung tip type of float needle. Best you do NOT use that method.
For these independent float conversion kits, here are some adjustment specifications:
With carburetor upside down the most outward part of the brass hinge unit, the top of its flat area, should be 10.5 mm and parallel to the base...AND...BOTH of these arms MUST be parallel to each other. For the old model 55 carburetors this was 8.5 mm. Once in operation, one could remove a bowl quickly, & the center area to top of the fuel should be very close to 1-5/32". NOTE that after first installing & adjusting one of these Bing independent float kits, they must be RE-ADUSTED after maybe a dozen hours of riding. This is because the float needle breaks in, & effects of fuel on the needle & float. I ALSO THINK the BRASS hinge unit tends to change, something to do with its hardness & tempering grade? It is important that the spring loaded plunger on the float needle be in good condition, & the spring inside it not sacked out nor rusted/frozen, or the mixture will be variable due to changes in the fuel level.
This is the original 1984 dated bulletin describing the new kit.
This is what Bing in the USA produced, & if you read it carefully, it differs a bit from the above bulletin.
Bing claims/claimed mileage increases. That is NOT likely ON A MOTORCYCLE, unless you were previously running rich from wrongly adjusted or bad floats; or, are so aggressive that you lean the bike WAY OVER like actually racing on a twisty race-course; or, you are doing VERY aggressive off-roading, with the bike often-times assuming very large angles. In my opinion, there will be no appreciable mileage increase from normal, even aggressive touring. I measured ZERO mileage improvement using very aggressive riding in steep tight twisties.
Bing ORIGINALLY offered these kits in various types, depending on your carburetor model number. These kits were offered for the slide carburetors as well as the CV carburetors. Kits were numbered #1 through 4 for BMW motorcycles:
#1: type 53 for R50, R60/5, and the /6 carbs.
#2: type for CV carburetors with 4 screws in the top cover.
#3: type for CV carburetors with 2 screws in the top cover.
#4: type for ALL 40 mm carburetors.
Kits #1 and #2 had the square grey float needles, requiring no needle clip.
kits #3 and #4 had the larger, triangular, brass, viton tipped needle with the needle clip.
In the clickable pdf that has a sketch, the 10.5 mm distance, which is 0.413", does not show that the bridge & carburetor base are also PARALLEL. This was added in a much later USA bulletin (which I have).
Bing promoted their new float system for transverse to direction engines, and for special industrial engines, ultra-light aircraft, etc., that had special inclination performance requirements. It is my beliefthat these kits were developed originally for small aerobatic aircraft & only later Bing decided it could sell many more, perhaps at a handsome profit, to motorcyclists and others, for whom there was REALLY no advantage, ONLY DISADVANTAGES (except floats life). As noted, I have the original Bing engineering bulletins on these kits, from the early 1980's...and most are clickable, see well above for the links.
Bing furnished, through its Bing Agency International in the USA, another bulletin that
explained how Bing wanted you to think about the kit's operation, using a glass of liquid as
an example, as liquid sloshed back & forth, with acceleration & deceleration, and how,
supposedly, this worked on BMW bikes (BUT....remember, our carburetors are rearward and angled, &
NOT a transverse engine!
Bing said that there is a lean-ness, then richness, power changed,
& you subconsciously added more throttle to compensate. I say: take this with a grain of salt!
"My Airhead motorcycle came with the twin independent float conversion... why do the gurus "hate" them? I also would like to know what IS the proper procedure for adjusting the float levels on carbs with this conversion, assuming I am going to do it myself ..." (and other inquiries.....).
I passed on what I knew about this kits as far back as 1984, and I later did articles
on these kits, including discussing the original engineering behind their development,
which Bing would probably prefer I not post.
NOTE that BMW never installed
them,... it would hardly have cost them anything...there are several reasons they did not, & I discuss those in the article you are now reading.
While I am often considered as one of the so-called "guru's", I actually have nothing too much against use of these Bing Independent Float Kits, or alcohol-proof kits, or however Bing Agency in the USA presently advertises and sells them. Just be sure your petcocks work properly (don't leak internally either) ....and are in the OFF position (horizontal lever position) if using the side-stand; OR using the center-stand.Pay attention to my advice to always turn off your petcocks when the engine is off (Bing ALSO now cautions this). This is especially important if using the side-stand. **** OFF is NOT "auf"!!!! if your petcocks are so marked!****
You will have to adjust the flimsy float bridge in the kits a few times, perhaps only twice. Usually, after that, they settle down & are reliable. You will still have to replace the float needle now & then, perhaps 30K-60K intervals, same as with the stock floats. You cannot replace the float needle without removing the kit's brass bridge...be very careful with it, as it is flimsy.
The twin independent floats in these kits "seem" to last forever in any type of gasoline or time/miles (NOT so the float needle).....but the adjustment brass-looking bridge is thin, flimsy & is poorly heat-treated. That brass-looking bridge needs to be adjusted properly at first install, & then once or twice more after being in use for awhile. Bing says readjust (implying once) after 5 hours, I say this is not enough, & should be checked again after maybe a month or more, and then maybe at yearly....or even longer, intervals; typically they are OK after they settle down. Depends on time & mileage. The float needles in all the CV carburetors were (very early models) a solid metal, and later Viton (or? rubber) tipped, and are now, per Bing, the same part number, no matter if the tip is black, gray, red, etc. Some early Bing carburetors had square metal ones, not triangular, in their bodies. The float needles in the Bing dual-independent kits are the same part as the later stock types. Float needles wear out ...and allow overflowing with the kit...and also with stock carburetors. USUALLY, there is a teeny bit of foreign matter lodged in the float needle seat or on the needle tip that you can remove by jiggling the float with the fuel turned ON, but, eventually the needles become unusable. The "Bing Dance" is the name given for jiggling the float in the stock carburetors to help the fuel flowing out on the ground to flush out debris in the float needle and its seat. For the stock floats, one needs only to not be too vigorous with that lifting and jiggling of the float. For the 'kit', you are moving, with your fingertip, the brass bridge. Be very careful not to bend it during the 'jiggle dance'.
BMW dealerships generally charge LESS for Bing carburetor parts than Bing Agency does, but the dealerships may...or may not... stock the independent float kit parts (as they are not BMW parts)...although the FLOAT needles are the same).
Details:At this point, if you have not looked at ALL FIVE bulletins/etc, links well above in this article,
CAUTION!If you are not familiar with Bing carburetors, you need to know that the thin round metal rod that holds the float bridge to the two carburetor support bosses, goes into, and is removed from, the support bosses from only one side. The rod is KNURLED at ONE end. The OTHER end goes in FIRST. When removing the old rod, remove it knurled end first; using a very thin rod at the NON-knurled end, and a very tiny hammer or even the plastic handle of some small tool as a VERY light tapping-impact tool!!...be GENTLE. You can devise a very thin rod for use as a square-ended drift, by grinding a nail, remove sharp end or reshaping it. Under NO CIRCUMSTANCES put much force on that float rod. When installing, tap it in or squeeze it in very gently. Remember: install the NON-knurled end of the rod first. That way, the knurled rod end goes into the knurled boss end, lastly. Be truly careful. You will have a VERY bad day if you break a boss.
Avoid miss-adjustment of the bridge....it could then cause rubbing, or uneven, even angular float operation. If you miss-adjust the bridge, you can get all sorts of problems, from flooding to mixture problems. This is NOT a difficult job, just be slow, cautious, careful.
Be careful about the two vertical float pins in each float bowl....those pins have been known to be bent, and
need gentle straightening; otherwise the floats might stick at the bottom (more, later on....).
On the Bing CV carbs, as STOCK, with the die-cast aluminum-looking (probably zinc) float bowls, there are two round holes, in the forward corners of the float bowls. ONE is plugged off, with the opposite one similarly plugged for the other carburetor, as there are left side & right side bowls. The one NOT plugged off is a 'well', with a small brass jet at the very bottom. That jet, on the stock or kit bowls, SHOULD BE checked for clogging. The well is where a small tube from the top body of the carburetor dips down into the well. CHECK THAT tube for condition. Some tubes have small side holes, that is normal. This tube is where the enrichener (mis-named choke) gets its fuel. Check the tube to be sure it is OK. On rare occasions folks have had carburetors with water in them & if the water freezes, the tube can split, & then you must repair that damage, with a sleeve. Note also, that the well/cavity needs an INTACT bowl gasket, that is the large cork gasket that fits into a groove at the bottom of the carburetor (float bowl removed to see it). If that gasket has a crack or missing piece in the area of the 'well', the enrichener may not work correctly.
The Bing "alcohol-proof" kits PLASTIC BOWLS (that I have seen so far) do NOT have ANY corners plugged, but the jet is for use in only ONE of the wells. Many early Bing kits were furnished with the jet in a baggy, UNinstalled. That was so YOU could install the jet in the correct corner. Your newly acquired bike, if it has these kits, should already have the jet properly installed at the correct corner...but do check that. Check this because as I noted, Bing shipped some kit bowls with NEITHER corner plugged off. It is possible that someone has a bowl with NO corner jet installed!...or in the wrong corner! The proper corner FOR THE JET is the one that mates to the small DOWNward pipe coming from the carburetor body corner. If the jet is not properly installed in the Bing Dual Independent kit, the 'choke' (enrichener) will not work correctly. In the stock metal bowls, you cannot fit the wrong left or right bowl due to the plug in one corner.
The jet is there to fill the 'well' in a controlled way, so that a very rich initial STARTING mixture is possible....and after approximately 10 seconds of running, the bowl is supplied by the quantity allowed by the JET. The downwards going tiny diameter pipe may have one or two teeny side holes, which modifies this, as far as bowl level that can be sucked up easily, but the idea here still holds. Thus, a jet NOT in the correct corner could allow some washing down of the cylinder walls with lots of fuel over too many seconds of operation which is not good. All of the metal dual-independent bowls I have personally seen have the jets already mounted in the proper corner. If you order a bowl, you are going to get the metal one; there is a LEFT & a RIGHT, due to this corner jet location.
If the float guide pins are bent, even a little, the floats can hang up!
I have also seen some floats with poorly peened tubes in the floats themselves, an easy fix.
First, turn the carburetor upside down. Adjust the tab on the bridge piece & the arms themselves, so the arms are parallel to the carburetor base and even with each other. Use a very small screwdriver, very carefully, to adjust the tab. The arms must also be parallel with the carburetor base & also the two arms parallel to each other. This condition must exist in future checks too. The distance per the Bing sketch of 10.5 mm (0.413") must exist.
5. If the carburetor is OFF the bike:
The part of the arm to look at for the parallel-ness is the BOTTOM of the arm, as viewed as if the carburetor was ON the bike. BOTH arms must be equal and parallel.
For 5. & 6: When using a small screwdriver, you bend the tab against the steel retaining pin. You will see what I mean when you try to figure out how to bend the tab. DO NOT BE HAM-FISTED.
7. A little known problem with the individual independent floats themselves is that there really is a top & bottom to SOME of them. Bing ignores this. Because of the tight fit at the bottom combined with the slight upward slope (and very close to the bowl rod) of the bottom of the 'new' float bowls, the floats CAN, sometimes, 'stick', to the bottom of the bowl. They can also stick at or near the bottom if the pin is bent even slightly!! Usually, but NOT always, this 'potential problem' does not cause a problem due to the motorcycle vibration during operation.
Be careful to install the floats on straight up pins. Another thing to watch for is that the center metal pipe area
(that is part of the float itself) is such that the broad-rivet head of that pipe is DOWNWARDS, towards the bottom
of the bowl. It is possible to actually 'feel' this float grabbing at the bottom, especially if the rounded larger head
area is up (or pin bent), instead of properly down...which raises the floats very slightly off the floor of the float
bowl. I had one bowl that I saw that this was exceptionally poor....so I installed the floats rivet pipe head
downward, and I put a very small and very thin washer over the bowl's rods first.
8. http://bmwmotorcycletech.info/bing-tech-bulletin.pdf has a sketch, near the bottom of the page, of the float bridge adjustment with the carburetor on the workbench, upside down. The RIGHT end of the arms (the two arm ends MUST be parallel) have a wider area on the right-most part of those arms. You could describe it as wider by a small amount. The UPPER surface of that wider part must be not only be parallel to the carb base body, and both arms even to each other....but the DISTANCE from this upper surface arm part to the carburetor base must be 10.5 mm...which is 0.412 inch. This covers all the CV carb models used on our Airheads (there is a different specification for ONE model of Bing not used on the Airheads...it is listed on the sketch above, model 55 carburetor, the distance is 8.5 mm).
9. After some hours of use, reset the bridge if needed, at the least do check it. The bridge will change its adjustment slightly due to its heat treatment (I THINK),....and some settling-in of the tip of the float needle...teeny changes in the internal float needle spring parts, etc. You will probably do this with the carburetors attached to the motorcycle, rather than remove them to the workbench. Mind my previous comments on how to do this with the carburetor ON THE BIKE.
You WILL have to change the float needle now & then, perhaps at 30,000 to 60,000 mile intervals. Rechecking adjustments is mandatory at that time...same as a stock carburetor. The adjustment of these twin independent float kit units is, as you have seen, a bit more time consuming than the simple adjustment method of the stock floats.
The lifting of the float bridge to see the exact contacting of the float needle pin plunger end is tricky. Certainly, no matter how done, you must be VERY gentle with the fingertip....to see the correct adjustment.....and to NOT distort the brass bridge. It might be a lot easier for you to turn the gas on & lift VERY gently to the point the gas JUST shuts off, then lower your finger to the point the gas JUST starts flowing. That is the parallel point....or should be. Be careful with that bridge. It is flimsy, & if you lift one at a time event without hardly any pressure, you can distort it..... both arms must remain parallel to each other, as well as the final adjustment being parallel to the carburetor body.
10. Once installed & in operation, one can turn off the fuel petcock(s), remove a bowl quickly to avoid excessive fuel getting into the bowl. The BOTTOM of the BOWL CENTER AREA to the TOP OF THE FUEL should be very close to 1-5/32". This was for a 40 mm Bing CV carburetor. I have not checked a 32 mm. When I do, will post it here:_________.
©Copyright, 2014, R. Fleischer
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Last check/edit: Monday, May 09, 2016