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Old 11-12-2005, 07:51 PM   #1
Tim McKittrick OP
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Location: Wasilla Alaska
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Bing dual floats- opinions wanted

I'm in the process of freshening up the carbs for my R100RT- I have a spare Bing dual float conversion kit lying about and am wondering if it is worth installing...... anyone out there care to chime in? Can this kit really improve fuel economy and HP? Is it a big fat waste of time? What have your experiences been?
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Old 11-12-2005, 08:39 PM   #2
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Location: Youngsville, North Carolina
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Bing dual floats

I installed the dual floats on my R75/5 several years ago but did not notice any change in fuel economy or hp. The principle sounds good but I do not believe that there is any significant improvements with these.

What I hear, I forget.
What I see, I remember.
What I do, I understand.

~ Chinese Proverb
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Old 11-12-2005, 11:02 PM   #3
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I think the dual float kit is designed for aircraft applications.

The only advantage (on a bike) is the plastic floats will probably last forever, versus the standard foam floats that die, sooner or later depending on what kind of fuels you use.

The big disadvantage is that the dual float kit eliminates the bowl overflow tube. So if you leave a petcock on and your floats stick, your cylinder could fill with fuel. When you try to start the bike, the cylinder hydrolocks and nasty things happen.

See Snowbum's web-site for more info.
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Old 11-13-2005, 12:09 AM   #4
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I can explain in detail, or I can render an opinion..... I'll do the latter.
Don't use the "new " system.
Back in YVR after riding around the world for 2 years.
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Old 11-13-2005, 04:18 AM   #5
Team Dennis
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Originally Posted by Malindi
I can explain in detail, or I can render an opinion..... I'll do the latter.
Don't use the "new " system.

If you can't share, don't play.

I was also interested in the conversion for my R100RS and almost bid on a kit on Ebay. Any info can make the un-informed make the right choice.
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Old 11-13-2005, 07:54 AM   #6
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I recently replaced my floats in one of my airheads, I didn't try these because I had never heard anything good about them. Here's what Snowbum one of the more respected airhead curmudgeons around had to say. He's a long winded character. JT

Joan, you have not been on the LIST long enough to have read the
thread(s) on those. I was first introduced to the darn things when
first released, and I have kept, all these years, for laughs, the
Bing Technical Bulletin of Nov. 1, 1984. I have posted about these
kits before, Oak has made comments in various publications about
them, and it was Oak who first pointed out to me, since I had
overlooked that bit on the bulletin, that there is no overflow
pipe. I have information on my website about the kits, but the
following is plenty good enough for a summary. They are a mixed
I sent SEVERAL inquiries, in a polite tone, to Bing, asking for
clarifications, they NEVER replied, in the slightest.
Here is a quickie won't hit all the points, but enough:

1. If they are so great, why did not BMW include them on the
airheads after 1984? On paper, the advantages seem good for
motorcycles, since we lean them, and have accelerations fore and aft
too. I can assure you that Bing would sell the updated carburetors
to BMW for, at most, PENNIES extra. Well Pfennigs.
2. They do NOT do what Bing claims they MANY respects. At
least in my testing.....and MOST of the feedback I have heard about.
Bing originally claimed increases in fuel economy, increased
horsepower, and 100% alcohol proof. BUT, those claims were ADDED to
the rear of the original bulletin!....and the original bulletin was
recommending them for transverse to direction of movement
motorcycles, and inclined industrial engines....and ultra-light
aircraft. It is MY understanding that they were developed
SPECIFICALLY for aircraft that turned upside down or at least did
quite steep manoevers;...and in which the carburetors might be
outward mounted. On the BMW they are angled inward some.
Lots more to this.
3. There is NO overflow pipe, like there is in the bowl of the
stock carburetor, hence if a float needle should not seal perfectly,
the overflowing fuel....motorycle parked...might just go into a
cylinder and liquid does not compress. The danger is then in trying
to start the bike...bending a rod or worse.....and if one cylinder
fired, the force is high....and, again, liquid does not compress.
Again, lots more to this. NOTE, that in fairness here, overflowing
Bings often just overflow out the 'vent' above the bowl...if the
overflow rate is higher than the center tube allows.
4. The kit is pricey. VERY pricey for what you get. Once can
purchase a lot of fuel for the cost.
5. The kit is very flimsy...the brass bridge parts are not heat
treated well at all, and after adjustment (yep, you have to adjust
these too), they need readjustment after awhile. If you are then
lucky, the adjustment will hold. The floats themselves seem fine.
6. My experience with them is that they are altogether too easy to
get just a wee bit off correct centering and adjustment, and then
can hang up. If one is careful, and adjusts them three
times...twice after initial setup after some weeks...they are
OK...sort of.
7. Whilst some have reported improvements in mileage, most others
report no change. Improvements MIGHT be due to just having new
floats and adjustments. Testing does not REALLY SEEM to show any
type of REAL improvement for most. I temper this with the FACT that
I have NOT tried them on a racetrack, nor under truly hard over to
the limits type of mountain riding. I have a number of miles, solo,
in rather brisk mountain twisty riding, on a /5, but I was unwilling
to push the bike to sliding around turns type of riding. It was not
my bike.

I also should inform you that I HAVE done some pretty good twisties,
over MANY miles, on TWO bikes equipped with these kits. ONE was the
above /5 I restored for Tandy Bozeman, that I rode (with Lilli on
her R80ST) from Tahoe to Redmond for the MOA National Rally, and
then more touring. I did not see any mileage increase....nor
decrease. /5s got good mileage anyway. I had to fiddle with the
/5 kits a LOT, to get them to work properly. NOTE that one must do
real comparisions in a good way, to get an idea of any mileage
increase. A PROPER test for an individual might be having the stock
setup, with proper float adjustment AND float condition, over
measured course, versus the new independent floats. I know of no
one that has done this and reported the details to me.

The other bike is my own solo bike, a stock engine, otherwise, 1984
R100RT (this bike, like the /5, came to me with those kits). I
have one good 400 or 500 mile mountain twisties type of trip, riding
double-up, on that bike. The mileage was OK...higher 30's. I
fiddled with those carb kits too...the float bridge is the problem
with them....and they are now stable in adjustment....I THINK...not
sure...will know in a couple of just putting the bike
back on the road after Winter Storage (don't ask).

8. My limited experience does not show if the new dual independent
floats are impervious to all the ingredients in modern gasoline's.
9. Be careful when removing the bowl to dump contents (as you
should, regularly)...the floats stay in the bowl, but are not tied
to it. This was brought home to me by one of our Members, who
shall remain forever anonymous...who contacted me...from the to speak......he thought he had some water in his gas,
pulled a bowl, and without thinking, tossed the gas contents....he
was in an area of lots of vegetation....he lost one of the floats
permanently. Wanted to know if I had a single one of those floats to
send him.

If you want to use these floats, it is fine by me, but you MUST set
up the float adjustment properly AND never leave the gas petcocks
ON, when on the sidestand. YOU MUST reset the floats AT LEAST once
more, after some miles. On these kits, the actual float bowl fuel
level is measured too. Bing's installation instructions are quite

snowbum #1843

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Old 11-13-2005, 08:56 AM   #7
Team Dennis
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Thanks JT for the informative read.
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Old 11-13-2005, 10:29 AM   #8
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I'll play by adding some data points

My '81 G/S had the kit when i got it, so i've been living with them for some years now. The standard of comparison is my '77 R100RS which had the normal white floats.

The RS would pee fuel occasionally for years until i became adept at accurately setting the float height. The G/S with the indy kit must've been well set up when i got it, b/c i've never had gas-boot while riding, ever. Snowbum alludes in his typically concise epic novel on the subject, it is very possible for the indy floats to hang up on their guides, and lead to flooding. I've never experienced this in running mode but it happens about 100% of the time after removing a bowl, refitting and then opening the petcock. As the bowl fills the floats bind on those little shafts and don't rise to meet the float needle. Standard procedure with mine is to lightly tap on the carb body with a small plastic mallet as the bowl fills-- this gives enough vibration to keep them from sticking. Once it's filled it's never an issue again until i have to take the bowl off the next time.

Performance gain? I suspect if there is any it is it so negligible as to still render the Bing marketing claims as bullshit.

Mileage? We R80 G/S'ers chimed in 2 weeks ago in a gas mileage thread here-- my max mileage with the kit (45mpg) sounds identical to everybody else's, many of whom are doubtless not running the kit. Again, if there is any increase, i'll bet you'd hafta squint *real* hard to see it.

More: I suspect at least 1 of my floats is getting out-of-spec heavy now, as i've had to lower the float height slightly in one carb to keep it from dribbling gas (this is somewhat half-assed confirmed by swapping in floats from the other pair/other carb). This is all loosely observational, and i need a rebuild regardless, but the point here is that if i determine i need to freshen things up with new floats, guess where i have to get them. Bada-Bing!!
And if i get all sassy and decide to return it to stock, i'll have to get stock bowls as well as the regular floats-- the indy kit bowls are incompat with the stocker floats.

Guess this is a literal case of YMMV

My .02 is that one will get waaay more benefit out of springing for new floats, float needles, needle jets etc (read: full rebuild) for the stock carb opposed to going for the independent kit.

I would recommend the tuning manual from the Bing Agency for the americas-- it was like $8 bucks a few years ago and has Snowbum-like data on the whole range of Bings fitted to BMWs, from slash/2 boxers and singles through 95.

Have fun, stay ventilated

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Old 11-13-2005, 12:27 PM   #9
Tim McKittrick OP
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Location: Wasilla Alaska
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Thanks for the replies- this is pretty much what I suspected. I don't have anything invested in the kit, and the only compelling reason I could see to install it is the age of the stock floats. Given that I have no signs that the old floats are bad- just old- I'll probably not bother with the dual float set-up.
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Old 12-15-2005, 01:51 PM   #10
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I put those dual floats in my GS before heading off to countries that have a lot of alcohol in the gas. I have had plenty of problems with the fact that there is no overflow on those float bowls. My whole top end fills with gas if I forget to turn off the fuel taps. To empty the hydrolocked top end, I take out the spark plugs and crank the engine over. But you aren't supposed to crank over the engine with out the spark plug wires beiing grounded. Once, when I wasn't thinking very hard, I put the plugs in the wires and layed them on the motor to ground them. Cranked over the engine, the 1000 cc of gas was expelled by the pistons, the spark plugs sparked and my motorcycle burst into flames. Those damn dual floats almost cost me my whole bike!
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