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The Bing Dual-Independent "Alcohol-proof" Float Kit
>>>A Bing, NOT a BMW-sold-nor-installed product!
© Copyright 2021, R. Fleischer
https://bmwmotorcycletech.info/bingindependent.htm
5
The MAIN advantage of these kits is that you are unlikely to ever have to replace floats again. That comment 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 when the needle is just about to be leaving the needle seat to allow fuel to flow into the bowl.
If the original floats are already bad, and/or the float needle is already 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 already worn, often considerably, is the HONEST, TRUE & ONLY reason that SOME find improvements with fuel mileage after their installation.
Adjustment of these dual-independent float kits is more involved than with the stock floats. These kits can CAUSE nasty $$$ problems, so read all of this article.
Introduction to these kits:
(I will get much deeper into them after this section)
I do NOT recommend Bing's so-called alcohol-proof independent float kits. HOWEVER; if you are willing to fiddle with these, & understand the limitations & cautions, they are OK. Bing published, decades ago, that they gave increased mileage & performance due to stability of the fuel level during turns. I somewhat agree, but mostly only in an aerobatic airplane or with serious racetrack use where the bike is leaned to truly extreme angles. These independent floats were originally advertised as being for engines where the carburetors were facing more left and right than on our Airheads ...& more or less fore & aft. One must think about the way the floats are hinged & operate, & then you will see that Bing's old claims for our bikes were hardly reality. As to their NOT being affected by 'alcohol'; ....that may be true. But, as seen in my Bing Floats article https://bmwmotorcycletech.info/bing-floats.htm, where I get into extreme long-term testing of floats in alcohols, alcohol-laced fuels, and MANY more chemicals, etc., alcohol is not the REAL problem that seems to cause deterioration of the stock floats, deterioration being, in particular, a weight increase, and probably a center-of-mass change.
For BOTH the stock or Independent Kits, you SHOULD replace the FLOAT NEEDLE regularly, and it is the SAME needle, for BOTH stock and the Bing Independent Float Kit. These Bing Independent float kits are very pricey. Consider what the kits cost versus your modest amount of labor if purchasing new stock floats every 30,000 (recommended by me) to 50,000 miles. Consider how many miles/time/etc., between the cost of a regular stock float replacement, versus the cost of Bing's Kit.
The Kits float levels are somewhat difficult to adjust. They need at least one adjustment some time after the initial installation and adjustment. ...Also....if not close to correct alignment the carburetors can flood.
CAUTION! WARNING!
There is NO provision for an overflow/vent for the independent float kits bowl, as in the stock float bowls. Thus it is possible for a serious problem with the left cylinder, if the motorcycle, especially if resting on the side-stand, has a leaking float needle and seat area, which is common to all Bing CV carburetors, kit or not. With a microscopic bit of filth/dirt/whatever, at the float needle/seat, the fuel does not shut completely off as the bowl fuel height reaches proper level. Instead, the bowl fills with fuel and this continues until the fuel overflows onto the ground (or your boot). THAT happens on the STOCK floats setup. But, with the KITS, there is NO overflow tube at the center of the bowl (leads to bowl outside bottom). Thus, there could be, in short storage, an overflow that fills the left cylinder with INCOMPRESSIBLE fuel which can destroy a piston & rod, upon you trying to start the bike. The overflowing fuel might flow to the ground from a further up carburetor body port, & not into the cylinder. I would not count on that. The situation with the kits installed can vary, if using the side-stand or on the center-stand. Having fuel in a cylinder, even a quite modest amount; and then, during starting, have the other cylinder fire-up, will usually cause enormous pressures in the then liquid-locked cylinder ...and a LOT of damage.
On the good side of things, the separate floats seem to be stable for any type of gasoline (so far as I have seen), and MIGHT last the life of the motorcycle.
Bing independent float kits may be seen with metal (zinc casting) bowls or with deep-reddish-brownish plastic bowls. There is a problem with the plastic bowls. Those bowls have been known to develop cracks, often microscopic, that cause weeping of gasoline, typically along a vertical corner. The latest Bing Independent kit bowls are zinc metal, similar in material to the original stock bowls. The kit bowls are rather costly to purchase from Bing if you needed to replace one (they did stop selling plastic ones). These special bowls are NOT available from BMW (note that BMW carburetor parts prices are often MUCH cheaper than Bing's). BMW does not sell these kits, nor kit parts (except the float needles).
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 per Bing's older 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 type of float needle. Best you do NOT use that method. I adjust float levels with the carburetors mounted on the bike.
For these independent float conversion kits, here are the adjustment specifications in case you do want to do this on the workbench:
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-ADJUSTED after maybe a dozen hours of riding. This is because the float needle breaks in, & the 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.
To adjust the kit floats: Maintain the arms parallel to each other. Adjust for 0.412" from the arm lower edge to the carburetor body, at the point your finger VERY LIGHTLY pressing on the arm assembly, causes the float needle plunger tip to NOT QUITE start moving upwards. When ON the bike, that adjustment is easier to do by just observing the point gas just stops flowing or just starts flowing ...that is the parallel point, or, should be. The part of the arm to look at for the parallel-ness is the BOTTOM of the arm.
Once in awhile deposits of fuel residues will get into the float needle spring and cause it to malfunction. The float needle tip also wears out (typically gets ridges, but may also just harden). Thus, the float needle should be replaced at regular intervals, just like the original stock ones, ...and they ARE the same part ....as delivered from BMW or Bing. I recommend 30,000 miles. It appears that the floats will NOT require replacing on the Bing KITS, at least no reports, so far.
Be sure the floats will operate very smoothly...their pins must NOT be bent; and the floats must NOT 'stick' to the float bowl bottom.
Links to .pdf articles on this website. These are actual Bing Bulletins. There is an explanation of how the Bing Dual-Independent Float kit conversions are supposed to work, & how they are to be adjusted, according to BING. Please read these Bulletins before reading further in this article.
https://bmwmotorcycletech.info/bing-tech-bulletin-1984.pdf
This is the original 1984 dated bulletin describing the new kit.
https://bmwmotorcycletech.info/bing-tech-bulletin.pdf
This is what Bing in the USA produced, & if you read it carefully, it differs a bit from the above bulletin.
https://bmwmotorcycletech.info/bing-tech-bulletin-1.pdf
https://bmwmotorcycletech.info/bing-tech-bulletin-2.pdf
https://bmwmotorcycletech.info/bing-tech-bulletin-3.pdf
Bing has claimed mileage increases. That is NOT likely ON AN AIRHEAD 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. Fore/aft large angles (wheelies? hard braking?) may also obtain slightly better fuel mileage. In my opinion, there will be no appreciable mileage increase ...from normal, even relatively aggressive touring/riding. I measured almost zero mileage improvement using aggressive riding in steep tight twisties .....in controlled conditions too. Instrumenting the bike for these measurements, which were about 3 miles each direction, multiple round trips, was difficult, but decent accuracy resulted.
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 carburetors.
#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).
The sketch also does not show that the distance is 8.5 mm, which is 0.335", for the model 55 carburetor ...but that model is not used on the BMW Airheads. The various types of Bing carburetors are used on vehicles other than BMW motorcycles, and if interested for some reason or other, know that the 53 carburetor (which is used on some Airheads) was made in 24-27 mm; the 84 in 28-32, the 54 in 34-40, and the 55 in 40-55. The 64 and 94 were the CV types.
Included in my personal files are original Bing Engineering bulletins from 1984 ....rather messily marked with my notes.
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 belief that these kits were developed originally for such, or likely 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 no advantage, 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 all that with a grain of salt!
Comments:
"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 similar 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 have preferred 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.
Primarily, there is the lack of an BOWL "overflow" that has "guru's" (& maybe BMW?) most upset. All the stock CV Bing carburetors, as delivered by BMW, have overflow capability at a vent port on the carburetor body, which is rather high up; and it does have a goodly capacity for flow. BUT: in addition there is the tiny diameter vertical 'overflow' (vent) pipe coming upwards from the bottom of the bowl. Neither of these may prevent some flow into the left cylinder, especially if the bike is on the side-stand, and the float needle is leaking ('allowing') fuel into the bowl above the proper level. Re-said differently, the float & its float needle are NOT shutting off the fuel, as the float bowl level rises to and above the proper preset amount.
In the old Bing books, Bing does not even address that bowl vent tube.
Side-stand's vary in their angle which is another factor. There is a great danger in trying to start the engine with liquid gasoline in the left cylinder. It does not take very much gasoline, as you try to crank the engine, to have what is called a 'liquid' or hydrostatic lock, which, especially if the right cylinder starts; can lead to left side busted piston, bent rod, etc. Just a FEW teaspoons-full of gasoline in the left cylinder is enough to cause serious damage, even if the right cylinder does NOT start. This is due to the movement of piston & rod during the time the powerful starter motor is attempting to crank the engine. The forces will vary with how much down the cylinder the piston was when a quite modest overflow into the cylinder began. Only some of this is due to the starter motor having time to get that piston moving fast. It could be a different story, perhaps worse, if the right cylinder fires-up ...but the end effect is the same: probably a bent left cylinder rod ...and maybe broken metal (piston, for example). Because the stock carburetors do have vents, any such problem with them is UNLIKELY.
With the Bing independent float kits, there is NO DIRECT BOWL VENT, which acts somewhat as an overflow. You can see this by looking at the Bing bowls in the kit, versus your stock bowl ...there is NO vertical tiny pipe anchored to the bottom in the conversion kit bowls. I was originally surprised to see this, as Bing could certainly have included one. Just why they did not is a good question!
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) ....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 now also cautions this). This is especially important if using the side-stand. Do NOT ever forget!
If your petcocks are marked with "auf", that does NOT mean fuel is off (look up auf in German, but do it thoroughly). In German, it has several meanings, but as an adverb it means ON.
You may have to adjust the flimsy float bridge in the kits a few times, but usually only once or twice. Usually, after that, they settle down & are reliable. You will have to replace the float needle now & then, perhaps at 30Kmi 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. You MUST check the metal float bridge adjustment after a float needle change.
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 after a year.
The float needles in all the CV carburetors were (very early models) 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 were square metal shaped. The float needles for later carburetors, 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. Vastly more often there is a teeny bit of foreign matter lodged in the float needle seat or on the needle tip that you can usually remove by jiggling the float with the fuel turned ON, but, eventually the needles do become unusable. The "Bing Dance" is the name given for jiggling the float, bowl temporarily removed, in the stock carburetors ....to help the fuel flowing out on the ground 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'.
Fuel hose recommendations have been moved to item #11 in https://bmwmotorcycletech.info/fuelmiscl.htm
The following is very slightly edited version of a reply I did to the Airheads LIST on 07/12/2017:
"There is NO proof that gas-o-hol (gasoline with alcohol added) is what is causing the original types of Bing one piece floats to deteriorate and get heavier. Bing advertised their $$$ float and float bowl conversion as "alcohol-proof". In my opinion, that is totally misleading. Bing could have simply changed all their white single piece float assemblies to whatever the new-fangled plastic independent floats are made of, heck, they could have just upped the price some, and gotten away with it and sold a LOT of floats. Some corporate types decided to foist the expensive and dangerous (no overflow) and flimsy kits onto us. Anyone who thinks those independent floats offer better mileage, and anything much else Bing advertised ....are invited to see the original Bing literature and other nice things in the article on my website. Of course, if you consistently loft the front wheel into the air, and keep it there for considerable distances, you will get better mileage with the Bing Independent Float Kits. They were designed for aerobatic airplanes of the home-built and factory experimental types, in my opinion. Not enough $ for Bing, limited opportunity for sales, so they offered them at rallies, etc....for us bikers. OF COURSE!,... if you were already running rich, due to heavier floats from aging from the fuel anti-corrosives and other additives, the kits offered increased mileage. So did new standard floats! You'd have to purchase a LOT of new standard one piece floats (30K+ intervals??) to pay for two kits!
"
Details, details, details:
At this point, if you have not looked at ALL FIVE bulletins, etc, links well above in this article, NOW is the time to do so. Read them at this point, before proceeding.
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 or call it direction. 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 tool of some sort at the NON-knurled end, and a very tiny hammer or even the plastic handle of some small tool as a VERY light impact tool!! ...BE GENTLE. You can devise a very thin rod for use as a square-ended drift, by grinding a small nail, remove sharp end or reshaping it. Under NO CIRCUMSTANCES put much force on that float rod. DO NOT do any prying with pliers when removing or reinstalling this pin. When installing, tap it in gently or squeeze it in gently. Reinstall the NON-knurled end of the rod first. 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 kit float bowl ....those pins have been known to be bent, and need gentle straightening; otherwise the floats might stick, even at the bottom (more, later on....).
On the Bing CV carbs, as STOCK, 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, and the small side hole in the casting 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 its condition. Some tubes have small side holes, that is normal. This tube is where the enrichener (miss-named choke) gets its fuel when you are starting a cold engine. On rare occasions folks have had carburetors with water in them that has frozen and the tube has 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 flimsy 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 sold early-on had PLASTIC BOWLS (there were some original metal ones too) & did not have any corners plugged & most early Bing kits were furnished with the corner enrichener jet uninstalled and in a baggy. That was so YOU could install the jet in the correct corner. It is possible that someone has bowls with NO corner jet installed! ...or in the wrong corner! The proper corner for the jet installation is the one that mates to the small downwards pipe coming from the carburetor body corner. If the jet is not properly installed in the Bing Dual Independent kit, the 'choke' (enrichener) CAN NOT work correctly. In the stock metal bowls, you cannot fit the wrong left or right bowl due to the plug in one corner. Later Bing kit bowls were metal, and all of the LATER metal dual-independent kit bowls I have personally seen have the jets already mounted in the proper corner. If you order a bowl, you should be getting the metal one; there is a LEFT & a RIGHT, due to the corner jet location.
The jet is there to fill the 'well' in a controlled way, so that a very rich initial STARTING mixture is possible using 'full choke' if wanted. After approximately 10+ seconds of running, the bowl is supplied by the quantity allowed by the corner JET (assuming maximum enrichener lever setting). That is all a somewhat simplified explanation. The downwards going tiny diameter pipe may have one or two teeny side holes, which modifies the operation. 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.
If the float vertical guide pins are bent, even a little, the floats can hang up!
I have seen some KIT floats with poorly peened tubes inside the floats, which can cause easy to overlook problems. This is an easy fix.
Adjustments:
Here are some hints from my own work on these:
1. Bowl CENTER to top of gasoline, ~1-5/32". This is APPROXIMATE & is for 40 mm carbs.
2. Carburetor is supposed to be upside down on an angle of 15 degrees or so for the original installation instructions. If adjustment is checked & done with carburetor on the engine, which is fine for future checks, the lower part of the spring-loaded plunger type needle, that is, the plunger, must be such that the plunger is JUST being touched/pressured, but the plunger has not moved upwards yet, for both the parallel and distance measurement. That is 0.413". Excessive pressure will depress the needle plunger and give a false reading. This measurement can be done by holding a flat wide steel rule against the lower part of the carb body & using another narrower rule marked at 0.413" MINUS the rule thickness, vertically from that, noting using fingertip & hardly the slightest pressure on the bridge, where the bottom of the bridge finger (either) is parallel & the measurement is correct. This is a pretty accurate adjustment point, rather better than #1, which can be used, with 'QUICK' bowl removal, as a double-check on your work. Better is on the workbench, but NOT necessary. See 5 and 6, below.
3. Hairclip is not used at float bridge tang area on 64-32/1 through 20. You could.
4. The spring loaded plunger type of float needle has a very tiny hole in the bottom of the plunger. That hole & the bridge tab, is mechanically coupled by a very easy-to-loose teensy wire clip. The purpose is to make for very positive opening of the float needle port. Assembly of the needle, clip, & float bridge are best done on the workbench, on a piece of old white bed sheet. YOU CAN do it on the bike, if careful ...and do put a white sheet on the floor! I always stock extra wire clips.
From here, I will assume the new twin independent floats kits were properly installed.
5. If the carburetor is OFF the bike:
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/parallel with each other. Use a very small screwdriver, very carefully, to adjust the tab. The arms must 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.
6. If the carburetor is ON the bike:
You have to lift the arm assembly VERY gently with a fingertip, and NOT ..NOT!....allowing the spring loaded plunger (if you have that type) in the float needle to be more than just barely touched. You CAN feel the resistance though ...just do NOT depress the needle plunger. Same adjustment(s) are to be done. The adjustment MAY be easier for you to do by observing the point gas just stops or just starts flowing ....that is the bridge parallel point, or, should be. The parallel point with the stock one-piece float assembly is parallel from top of floats to carburetor bottom of its body.
The part of the arm to look at for the parallel-ness of the KIT 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. The float kit parts can be thought of, as you have been concluding from reading here, 'delicate'. Little things you might overlook, can cause problems. Such a situation can occur with something (of several!) I noticed, that no one else ever reported, including Bing. There really is a top & bottom (or, should be considered as so) to SOME of these floats. 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 does not cause a problem due to the motorcycle vibration during operation. I do not take the chance. 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. https://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 0.413 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 time, 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 more simple adjustment of the stock floats.
The lifting of the float bridge to see the exact contacting of the float needle pin plunger end is slightly tricky. Certainly, no matter how done, you must be very gentle with your 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 ....AND 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 from the fuel in the hose, etc., above, but below the petcock). 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 carb. When I do, will post it here:_________.
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.
Revisions:
02/18/2005: Clarifications and final release.
05/22/2005: Add extensive notes, yellow background.
05/24/2005: Add 4 scanned pages, modify descriptions, minor other things.
08/24/2005: Go over article and clarify some details.
06/24/2007: Edit the article for clarity, add more cautions.
01/10/2008: Rechecked article.
04/13/2009: Fix very minor typos and clarified a couple of details.
09/13/2009: Correct typo in ...OK.... pay attention here!::: area, where I had 19.5 mm instead of proper 10.5 mm.
05/17/2011: Slight cleanup. Still a very messy article!
09/19/2012: Add QR code and update google code and fix a couple of unimportant spelling typos.
04/30/2013: Complete re-do of the article. Add two bulletins, remove one, re-arrange article, clarify details, etc.
05/13/2013: Add the Bing 1984 original bulletin bing-tech-bulletin-1984.pdf.
05/14/2013: Clear up a minor confusing point.
02/08/2014: Revise several areas to avoid confusion with statements about bowls; clear up typos; remove confusing information about bowl gasket.
09/12/2015: Clean up article.
01/08/2016: Meta-codes; left formatting; horizontal separators; narrow the article. minor clarifications 01/11/2016.
05/09/2016: Final updating of metacodes, formatting, colors, fonts, scripting, H.Lines, minor clarifications. Additional cleanup of colors/fonts 05/28/2017.
07/12/2017: Add section: Yet MORE! comments.
12/06/2017: Go though entire article. Eliminate excessive html, greatly reduce use of colors and fonts changes. Improve clarity of explanations.
09/08/2018: Punctuation, grammar.
08/10/2019: Clean up descriptions slightly here and there, for better comprehension.
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