Ethanol and carb float problems . . .

[CTellman]

In the Feb ON there is a discussion about ethanol and the effect on the carb floats on airheads. Has anyone experienced their tank floats losing buoyancy? I looked at Bob's catalogue and while they offer a conventional float, they don't specifically mention an ethanol resistant float.
My fuel tank liner paint is flaking off. I have cleaned it out and hopefully it is OK. Do I need to get tank recoated?
Thanks,
Campbell Tellman II
'93 R100RT
:thumb

[jpberens43639]

The BING agency makes a float kit for this. I've had one in my 1981 R100RS for over 15 years.

" www.bingcarburetor.com " or Google BING Carbs.

I think you MAY need to at least clean your tank out. I drain & wash mine out every couple of years.

[vanzen]

I had experienced loss of Bing float buoyancy (type 94 CD carbs)–
not sure that the cause was ethanol,
(I was in Colorado where the gas contained a higher ethanol %)
or old age (the floats were @ 13 years old).

And bought the Bing "air-craft style" float kit as used by jpberens43639.
Bing advertised, among other "benefits", that the floats are alcohol resistant,
which, to my years of use, is substantiated.

I am happy with the kit, have had ZERO problems with it, however,
as to the original Bing advertising claims of "improved mileage and performance" –
dubious at best.

[88bmwJeff]

Bing now sells two versions of the alcohol resistant floats. The independent float kit, which also comes with new bowls, has been around for 15+ years based on the previous posts. This independent float kit has had mixed comments over the years. More recently, Bing came out with a hinged, non-independent float, which is a direct replacement for the OEM white ones. I have yet to come across anyone who has purchased the hinged version. If anyone has, please post and let us know.

edit: I would clean and drain your tank annually. When there's too much paint on the petcock filters, then you know it's time to re-coat the tank. That's my $0.02

[CTellman]

Is a recoat required? Who does it? How much $?
Thanks,
Campbell Tellman II
'93 R100RT
:thumb

[Bill Burke]

Is a recoat required? Who does it? How much $?
Thanks,
Campbell Tellman II
'93 R100RT
:thumb
The answers: Yes. You. About $50. The whole process, if done right, takes a good week or so. A real PITA, but worth it. I recommend POR-15.

[PGlaves]

My comments in Benchwrenching in the February ON were directed specifically at:

1. OEM white foam floats. The ethanol dissolves the laquer and the foam absorbs gas. Floats get heavy, and upset the fuel level at the least, and sink to the bottom of the bowl and drip fuel all over at the worst.

2. The black plastic split float system that comes with an unvented/non-overflow bowl - that meter fuel less well and can cause other problems.

I have no experience with the new plastic hinged floats, but if they a) replace the foam floats and work the same; and b) have a vented bowl with overflow tube - then they should work fine.

I did get one email inquiring if I also meant the vintage floats on /2 bikes, etc. They are soldered brass. Ethanol can cause corrosion of the brass but it would take an awful long time. The solder might be more susceptible to corrosion than the brass.

[20774]

I did get one email inquiring if I also meant the vintage floats on /2 bikes, etc. They are soldered brass. Ethanol can cause corrosion of the brass but it would take an awful long time. The solder might be more susceptible to corrosion than the brass.

They tend to get cracks from a process called work hardening. They'll crack just sitting on the shelf. Once cracked, gas gets inside and they sink. I understand that Vech offers plastic floats for /2s now that eliminate this problem. Plastic, not foam as I understand it.

[vanzen]

...
edit: I would clean and drain your tank annually. When there's too much paint on the petcock filters, then you know it's time to re-coat the tank. That's my $0.02


won't help saturated floats, but...
good idea.

that paint (tank liner) can and will chunk off into bits
rattle around inside the tank
knock the screen filters off the petcocks
and make their way into the carbs
causing pure mayhem ...

in addition to coating and blocking those screens,
possibly interrupting fuel delivery.





don't ask.

[widebmw]

My comments in Benchwrenching in the February ON were directed specifically at:

2. The black plastic split float system that comes with an unvented/non-overflow bowl - that meter fuel less well and can cause other problems.


I had the Bing dual float kit on my R80 for 50,000 miles than I moved it to my
R100R for another 50,000 miles.

Then I put 40mm bings on my R100R and a new dual float kit on that bike.
I have 255,000 on that bike and I have been very happy with that kit.

What is the metering problem ?
What other problems ?

I have heard others say that they have heard of problems but I have not had any.

[47512]

Paul, I have had the independent floats and bowls on a R75/6 for about 15 years with no issues, but I have heard of others that have had running probblems. Mikuni has used the independent float system for dirt bike applacations for years.

I have several old British bikes with Amal carbs, Amal floats are holow, the new fuels make them crack and leak. Another issue is with fiber glass fuel tanks, it seems that the alcohol in the fuel slowly desolves the resin and it ends up a sticky mess on the slides and intake valves.

Ducati has had probblems with the U.S. fuels atacking the plastics in their fuel tanks, making them expand, leak, etc. I have seen the effects the alcohol has on the viberation damper for the fuel pumps on the older K series BMW's as you describe in your artical. This also happens to some of the older German cars with the fuel pump in the tank.

Ken G.

[88bmwJeff]

won't help saturated floats, but...
good idea.


I agree, but CTellman also indicated that the paint liner in his tank is flaking off, and my comments about cleaning and re-coating the tank was in reference to that.

[6659]

"Another issue is with fiber glass fuel tanks, it seems that the alcohol in the fuel slowly desolves the resin and it ends up a sticky mess on the slides and intake valves. "

I have an MZ Skorpion that has a plastic or fiberglass tank. Can't be sure other than it not being metal. I noticed that the sides of the tank has waves in it recently. I though it might have something to do with the "Stabil" I put in it but when I contacted the manufacturer, he said it must be due to the alcohol. What, as consumers, are we supposed to do as the government sets out to destroy all the old vehicles on the road?

[beemrtim]

I would like to know how the Delorto carbs on the R90S hold up with this fuel.

Anybody got an answer?
T

[PGlaves]

I had the Bing dual float kit on my R80 for 50,000 miles than I moved it to my
R100R for another 50,000 miles.

Then I put 40mm bings on my R100R and a new dual float kit on that bike.
I have 255,000 on that bike and I have been very happy with that kit.

What is the metering problem ?
What other problems ?

I have heard others say that they have heard of problems but I have not had any.

Well, first off, don't ever leave a petcock turned on by accident. If the needle seeps the bowl fills up, and the fuel then flows into a cylinder. Then - if you are lucky - when you start the engine the damage is to the bottom end from the gasoline diluted oil. If you are slightly less lucky one cylinder will hydrostatic lock from the gasoline in the cylinder. If perchance the other cylinder fires just once you will have a bent rod or two to contend with. If that cylinder doesn't fire you will probably get by with just a broken starter nose casting.

Beyond that, your mixture is likely to cycle between too rich and too lean from time to time - especially in the twisties - because despite the claims, the fuel metering is less precise, not more precise. Too rich just robs you of performance; too lean can damage valves and even pistons.

But other than that they are just fine. You like them and it's your bike so feel free to use them. I wouldn't, but it's not my bike.

[Manfred]

My brother (a long time BMW owner/rider) warned me about this float problem when I bought my boxer in December. He thinks my carburetors have "good floats". I guess I'll drop the bowl on a carb this weekend and see what's there.

[beemrtim]

Paul G: Do you know of any ethenol nrelated problems with the Delorto carbs?

[Red100RT]

Does anyone know of a chemical that can be used to coat or re-coat the oem floats that can stand up to gas/alcohol? What would varathane do?

[PGlaves]

Paul G: Do you know of any ethenol nrelated problems with the Delorto carbs?

I don't - but I have little experience with the Delorto carbs in recent times.

This is probably a good question to post over on the Airhead Club list. I'm pretty sure Tom Cutter is likely to have an answer, as well as others.

[DennisDarrow]

So Paul, what do you recommend doing about the float situation. Obviously you are not in favor of the floats that do not absorb or deteriorate because of the problems you outlined............thanks......Dennis

[PGlaves]

So Paul, what do you recommend doing about the float situation. Obviously you are not in favor of the floats that do not absorb or deteriorate because of the problems you outlined............thanks......Dennis

I discussed this a couple of weeks ago (Supertech in Pennsylvania) when it came up in a Q&A Tom Cutter and I were doing. I think there are two possibilities:

1. Just replace the foam floats fairly often - every year or so. If they look brown, or you are getting dribbling, then replace them.

2. I am told - but have not seen - a new float which is a single hinged float assembly that looks in shape like the original foam floats - but which has hollow black plastic floats on the hinge. I am also told that these floats retain the use of the OEM vented float bowls with the overflow drain tube. Assuming these were described to me correctly they are what I would use.

[osbornk]

I discussed this a couple of weeks ago (Supertech in Pennsylvania) when it came up in a Q&A Tom Cutter and I were doing. I think there are two possibilities:

1. Just replace the foam floats fairly often - every year or so. If they look brown, or you are getting dribbling, then replace them.

2. I am told - but have not seen - a new float which is a single hinged float assembly that looks in shape like the original foam floats - but which has hollow black plastic floats on the hinge. I am also told that these floats retain the use of the OEM vented float bowls with the overflow drain tube. Assuming these were described to me correctly they are what I would use.

would it be possible to coat the foam floats with a more alcohol resistant coating? (like polyurathane) I can still get 100% gas but I don't know for how long.

[donbmw]

I discussed this a couple of weeks ago (Supertech in Pennsylvania) when it came up in a Q&A Tom Cutter and I were doing. I think there are two possibilities:

1. Just replace the foam floats fairly often - every year or so. If they look brown, or you are getting dribbling, then replace them.

2. I am told - but have not seen - a new float which is a single hinged float assembly that looks in shape like the original foam floats - but which has hollow black plastic floats on the hinge. I am also told that these floats retain the use of the OEM vented float bowls with the overflow drain tube. Assuming these were described to me correctly they are what I would use.

You can get the new floats from the Bing Agency International L.L.C. I got some this summer and have not had anyproblems with them.

Don

[Red100RT]

would it be possible to coat the foam floats with a more alcohol resistant coating? (like polyurathane) I can still get 100% gas but I don't know for how long.

Well, I am going to do just that. I am going to remove floats and clean them then coat with polyurathane (varathane) and let cure for a week or so then let soak in ethanol for a week and if all is well use them. Apparently the oem floats are coated with some kind of varnish and polyurathane is supposed to be alcohol resistant.

[PGlaves]

Well, I am going to do just that. I am going to remove floats and clean them then coat with polyurathane (varathane) and let cure for a week or so then let soak in ethanol for a week and if all is well use them. Apparently the oem floats are coated with some kind of varnish and polyurathane is supposed to be alcohol resistant.

Please let us know what happens. This may be very useful!!

[04R1150RS]

I just put the new single hinged floats on my G/S which are a direct replacement for the originals, no problems yet, but have only been on the bike for 1.5 months. The other kit offered by Bing is insanely expensive, have to buy the bowls too. That's ridiculous!!!!

[PGlaves]

I just put the new single hinged floats on my G/S which are a direct replacement for the originals, no problems yet, but have only been on the bike for 1.5 months. The other kit offered by Bing is insanely expensive, have to buy the bowls too. That's ridiculous!!!!

And as stated before - the unvented bowls are a disaster waiting to happen.

[fracture]

Well, I am going to do just that. I am going to remove floats and clean them then coat with polyurathane (varathane) and let cure for a week or so then let soak in ethanol for a week and if all is well use them. Apparently the oem floats are coated with some kind of varnish and polyurathane is supposed to be alcohol resistant.

Just wondering about something: If the oem floats are coated with some kind of varnish, and another coat of some type is added, will the floats "sink" a bit more due to the added weight, therefore requiring some other adjustment to keep fuel level in the bowl at the specified height?

That one extra coat may not seem like much weight to you and me, but to the float it may be quite a bit.

I am concerned about the ethanol/float issue. I have the original floats and they have been holding up for about 15 years. I have not noticed any problems due to floats deteriorating from the ethanol. Fuel with 10% ethanol is the norm where I live.

[Manfred]

And as stated before - the unvented bowls are a disaster waiting to happen.

I've looked at my carbs amd the diagrams for them and don't see any overflow vents. Where are they located?

[James.A]

The overflow is the little brass tube that stands straight up from the bottom of the float bowl. It extends slightly above the top of the bowl. Float bowls for tickler-type carbs, like the type 53, don't have them.

I would also like to know more about coating foam floats or plastic hinged floats.

[CTellman]

For the uninitiated . . .can vented floatbowls be retrofitted to 40mm Bings?
Campbell Tellman II
'93 R100RT
:thumb

[Red100RT]

Please let us know what happens. This may be very useful!!

Well, I coated the floats with polyurethane (3 coats) let cure for 5 days and after about 3 hours in ethanol e10 the polyurethane commenced to peel right off. Long and short is it don't work:banghead :banghead

[CTellman]

I bet WEST System or some brand of epoxy would do it . . . .
Campbell Tellman II
'93 R100RT
:thumb

[Red100RT]

I bet WEST System or some brand of epoxy would do it . . . .
Campbell Tellman II
'93 R100RT
:thumb

Epoxy hmmmmmmm... I might try something like that since I am not sure if I can remove all the polyurethane and if I am not sure all is removed then I am not about to install the floats least I live to regret it.

[osbornk]

Epoxy hmmmmmmm... I might try something like that since I am not sure if I can remove all the polyurethane and if I am not sure all is removed then I am not about to install the floats least I live to regret it.

If you can't get it all off, the new coating would protect it from the ethanol and it would not hurt anything. I felt sure polyurethane would work. Darn

[Rod Sheridan]

Does anyone know of a chemical that can be used to coat or re-coat the oem floats that can stand up to gas/alcohol? What would varathane do?


1) nope

2) change the weight of the floats


Regards, Rod.

[Red100RT]

Have ordered a KBS tank sealer kit and plan to not only coat the interior of the gas tank but will dip the floats in the stuff as well and see what happens. As far as increasing the weight of the floats goes I'm not concerned as there is an adjustment for float level, just slightly bend the metal tab that pushes against the needle valve to adjust the level of fuel in the float bowls. Other scenario is to bite the old bullet and shell out $186 for a pair of ethanol proof floats from Bing Vergaser.
Could come to that.:banghead Who is the idiot that came up with this e10 brainstorm anyway?

Winter......I HATE IT:banghead

[osbornk]

Have ordered a KBS tank sealer kit and plan to not only coat the interior of the gas tank but will dip the floats in the stuff as well and see what happens. As far as increasing the weight of the floats goes I'm not concerned as there is an adjustment for float level, just slightly bend the metal tab that pushes against the needle valve to adjust the level of fuel in the float bowls. Other scenario is to bite the old bullet and shell out $186 for a pair of ethanol proof floats from Bing Vergaser.
Could come to that.:banghead Who is the idiot that came up with this e10 brainstorm anyway?

Winter......I HATE IT:banghead

Congress came up with e10. I'll wager your congressman and senators voted for it.

[cactuspat]

there many reasons against anding weight to the floats ,that tab is easy to bend for a reason, because it was made in accordance with the weight of the float without any thing extra on it, for one.

[Red100RT]

there many reasons against anding weight to the floats ,that tab is easy to bend for a reason, because it was made in accordance with the weight of the float without any thing extra on it, for one.

Actually, the tab doesn't bend easily. The tank coat kit arrives this Friday and I will let you know how it works out or not.

[88bmwJeff]

Other scenario is to bite the old bullet and shell out $186 for a pair of ethanol proof floats from Bing Vergaser.

A $186. I wouldn't pay that. For less than half that $70 you can get hinged alcohol resistant floats. The independent float kit with new bowls etc. is $186.

[Raceydog]

I discussed this a couple of weeks ago (Supertech in Pennsylvania) when it came up in a Q&A Tom Cutter and I were doing. I think there are two possibilities:

1. Just replace the foam floats fairly often - every year or so. If they look brown, or you are getting dribbling, then replace them.

2. I am told - but have not seen - a new float which is a single hinged float assembly that looks in shape like the original foam floats - but which has hollow black plastic floats on the hinge. I am also told that these floats retain the use of the OEM vented float bowls with the overflow drain tube. Assuming these were described to me correctly they are what I would use.

Did you ever find out what kind of floats they were? Or where to get them?

[Raceydog]

A $186. I wouldn't pay that. For less than half that $70 you can get hinged alcohol resistant floats. The independent float kit with new bowls etc. is $186.

Where can I get the set of hinged floats? They aren't on the Bing website and the guy didn't seem to know anything about them.

[20774]

Where can I get the set of hinged floats? They aren't on the Bing website and the guy didn't seem to know anything about them.

That's strange...I saw the new hinged floats (they were blackish in color) at the National Rally in Johnson City. The Bing guy was there in the main vendor area. They're shaped just like the original white foam floats but are black in color.

Bing's website is not as complete as it could be. I'd be persistent and call them back or check with a BMW dealer. They can get carb parts as well.

Captial Cycle lists an alcohol resistant float for '70-on twins for $15. The picture shows the stock white float...that's not correct unless they're just lazy with their pictures. They list part number 13 11 1 254 766. This part number is the same on other websites showing the stock white float.

[Manfred]

Bottom of this page - pricing not on this page, however. http://bingcarburetor.com/bmw/bmwcvkits.html

[20774]

Manfred -

You reference the "older" independent floats....different animal. Bing has come out with replacement floats for the old white ones. They look identical, mount the same way, but are alcohol resistant. The independent floats require a change in the float bowl (with the elimination of the overflow) and have a somewhat difficult process to set up the floats.

[AnnapolisAirhead]

... Bing has come out with replacement floats for the old white ones. They look identical, mount the same way, but are alcohol resistant. ...

This is very good news. So what are the BMW dealers carrying? I mean, why wouldn't everyone convert to alcohol resistant floats?

[20774]

Tony -

I would think you could get everything at the dealer...you'd have to specify the new kind. Of course, I'm sure Bing sells them direct...I don't know how new they are but I looked at them at their booth at the National.

[scjack]

Around four years ago, I installed the independent, black floats & bowls on a 1978, R100S. They were not that difficult to set up but I didn't get any better gas mileage and they were not that expensive. I sold that bike and haven't looked at the Bing price list lately. I was very surprised to see how much they're presently asking for this kit. I wouldn't spend that much money to do the conversion, especially since the white floats are now alcohol resistant.

[20774]

especially since the white floats are now alcohol resistant.

That's not my understanding...the white floats are same-old-same old AFAIK. The newer alcohol resistant floats are a carbon black or dark gray in color or something. That's what I saw at Johnson City.

[jforgo]

I would think BMW would have a new part number if their current floats were functionally different.
Ethanol perhaps not an issue in Europe?
The black ones on Bing website seem interesting - but no part number, or pricing, so who knows if these are even in ptoduction

[scjack]

That's not my understanding...the white floats are same-old-same old AFAIK. The newer alcohol resistant floats are a carbon black or dark gray in color or something. That's what I saw at Johnson City.

You are correct. I meant to say "black" (but they look like the older white ones).

[Red100RT]

Don't remember if I posted about my soaking the floats in KBS Coating at the same time I cleaned and coated my tank with KBS product but I did this number last early spring with what looks to be success. Floats look good after a riding season and coating didn't seem to require resetting the float levels. I don't ride in the winter months for obvious reasons and I always drain the tank and empty float bowls and give them a liberal shot of WD-40. Also changed out fuel lines to lines sold by Bing. Probably could have bought similar product from NAPA for maybe less, who knows.

[Raceydog]

The only black floats I have been able to find are the ones that come with the 200 dollar kit with replacement bowls and the ones for the CV carbs. I have an R50/5 which has a type 53.

[3moskvichi]

You can minimize the problem altogether by limiting the time the floats are exposed to gas. About half a mile before I get home, maybe less, I turn off the petcocks so that when the bike is parked, the float bowls contain little or no gas. That way the floats aren't sitting there soaking in fuel. The only time they're immersed in fuel is when I'm riding.

[PGlaves]

You can minimize the problem altogether by limiting the time the floats are exposed to gas. About half a mile before I get home, maybe less, I turn off the petcocks so that when the bike is parked, the float bowls contain little or no gas. That way the floats aren't sitting there soaking in fuel. The only time they're immersed in fuel is when I'm riding.

My grandpa used to have to do this with his 1921 Ford. Ah, the wonders of technology.

[69zeff65]

I have heard there is an additive for the ethonal gas that inhibites the properties of the ethonal. Sta-bil introduced it because of all the problems in the marine industry. Tanks delaiminating and carbs going south seemingly overnight. Our lovely goverment and all the power and $$$ grubbing politicos are squarely to blame for this problem. FIRE THEM ALL

[Typ181R90]

I have heard there is an additive for the ethonal gas that inhibites the properties of the ethonal. Sta-bil introduced it because of all the problems in the marine industry. Tanks delaiminating and carbs going south seemingly overnight. Our lovely goverment and all the power and $$$ grubbing politicos are squarely to blame for this problem. FIRE THEM ALL


I think you might mean this: http://mystarbrite.com/startron/

My local bmw dealer has it and I gave it a shot at my last tank fill. I have noticed the bike ran a slight bit smoother but as I haven't filled my next tank I haven't noticed if it improved fuel economy or had any other effects

[Raceydog]

You can minimize the problem altogether by limiting the time the floats are exposed to gas. About half a mile before I get home, maybe less, I turn off the petcocks so that when the bike is parked, the float bowls contain little or no gas. That way the floats aren't sitting there soaking in fuel. The only time they're immersed in fuel is when I'm riding.

I have started doing that too. We'll see how it works on the new white floats I installed today. While I have everyone's attention, I have another question. The specs in the clymer manual say the floats should be 10 grams. The old ones were 14 and 15 grams each and were original bing floats. The new ones are 12 grams each. Should they be shaved down on top to bring them down to 10? Sounds crazy, but I am trying to minimize flooding/leaking and I really need to have these carbs running smoother.

[beemerPhil]

Geez, what a lot of haggling over nothing!
:fight

RELAX. Your bike is ok.:banghead

In the first place, float height is NOT THAT CRITICAL. Within reason is fine, no need to beat the thing down to the last .001".

The ethanol problem isn't that severe- I've seen saturated floats, of course, but not on every bike that comes through the door. Fuels vary, some are pretty snotty, most are ok.

Ethanol saturation doesn't become a problem til the float is significantly heavier than a new float, and begins to sit lower in the fuel. New floats weigh, IIRR, 10 grams. Worried? Weigh the floats. Or save your time worry and just replace them every couple years. They're cheap- are you?

Don't gas up at Discount Petrobarf. Don't add every available solvent fuel additive, that's just asking for trouble. Coating the floats with anything will make them heavier a lot faster than ethanol.....and if the stuff flakes/drools off, you have a new problem.

Ethanol-proof floats are great, but you're still gonna be into those carbs every year or so- airhead CV's need o-rings pretty regularly, and diaphragms every couple/3 years too. They're not maintenence free, and they're not gonna be. Live with it. That's why they made the bowls come off so easy.

I've installed the independent Bing floats for others, without any great problems; never used them myself, because it seemed a lot of money for.....well, nothing. I replaced my floats once in a while and never had any problems with them.

It's a smart practice to shut off the gas when you stop. The overflow stand tube in the float bowl is tiny- if you have a major float valve leak, it can still fill the cylinder just fine, while the overflow tube is draining full tilt. The tube isn't big enough to be a 100% solution. Besides, gasoline is....um.....flammable? Do you want a puddle of the stuff under your scoot, waiting for some moron with a cigarette?

I don't recommend shutting the gas off before you stop. (really? you really do that?) What if it stalls right before the semi changes lanes?

I've been draining and re-soldering cracked brass floats for....40 years? I don't see any more of them now than I remember seeing in the past, so it's hard to attribute a sudden rash of them to ethanol. I think they just crack from thermal stress over time- the brass is pretty thin. I mean, it's a float- and brass normally doesn't, so......

Who came up with ethanol? As usual, some well-intentioned, misinformed, smiling bobblehead in DC.
Politicians like it- another smiling baby to kiss, and a chip they can throw to those pesky environmentalists.
Gas retailers like it- they get to sell more gas. Ever check your mileage on gas vs ethanol?
Farmers love it- quadrupled the market price of feed corn overnight. Used to be a trash crop!
Rough on the water, though- corn farming is nitrate-intensive, and most of the nitrates applied wind up as runoff. Fish don't like it much. I hear there's a 600-square-mile dead zone at the mouth of the Mississippi........oh well. It's always something.

:violin


Want to haggle over something useful you can do for your Bings? Find a way to keep blow-by oil mist out of your idle circuit. Figure out what to use instead of a cold-start valve cover gasket.

Tune in next week for another episode of "As the Airhead Turns".........


Remember- it's not really rocket science til it gets past the clouds, no matter what they call it.

:wave

But if you're a real BMW perfectionist, I've got one last pair of titanium-plated Bing floats that Tom Cutter and I made in his basement back in the '80s, that I could let go for $300.

Each. :brad


YMMV!

[20774]

The specs in the clymer manual say the floats should be 10 grams. The old ones were 14 and 15 grams each and were original bing floats. The new ones are 12 grams each. Should they be shaved down on top to bring them down to 10?

I've not heard of this spec...I see no reason to modify brand new floats. Snowbum did some testing on a number of new/used floats:

http://bmwmotorcycletech.info/bingcv.htm

Just clean your carb and passageways, set the carb up properly, and there should be no real problems with leaking. They really do work fine.

[AnnapolisAirhead]

While I have everyone's attention, I have another question. The specs in the clymer manual say the floats should be 10 grams. The old ones were 14 and 15 grams each and were original bing floats. The new ones are 12 grams each. Should they be shaved down on top to bring them down to 10? Sounds crazy, but I am trying to minimize flooding/leaking and I really need to have these carbs running smoother.

+1 on a lot of fuss over nothing really. Shaving your floats to make your carbs run smoother? Ain't gunna happen IMO.

Those specs are akin to a speed limit sign or the line on a shot glass--technically those are the rules, but in reality they are only estimates/guidelines. Your o-rings, jets, cleanliness of the fuel circuit and balancing will help your road tractor run smoother.

[jforgo]

I have started doing that too. We'll see how it works on the new white floats I installed today. While I have everyone's attention, I have another question. The specs in the clymer manual say the floats should be 10 grams. The old ones were 14 and 15 grams each and were original bing floats. The new ones are 12 grams each. Should they be shaved down on top to bring them down to 10? Sounds crazy, but I am trying to minimize flooding/leaking and I really need to have these carbs running smoother.

I had some other thoughts about this, but then I see you are running an R50/5. A lot of the info and responses here will be based on the Bing CV's, which you do not have.
So my only suggestions which might be useful for your specific carbs would be;
Clean the carbs
Replace fuel line with something less sensitive to alcohol - found that braided looking fuel line from the dealer really leaches out from the alcohol - leaving black goo in the carbs
Take the bike for a 15 minute ride before attempting carb synchronization. Garage warmup doesn't cut it.

hopefully someone running slide carbs will have some other info for you.....

[AnnapolisAirhead]

I had some other thoughts about this, but then I see you are running an R50/5. A lot of the info and responses here will be based on the Bing CV's, which you do not have......

He probably has the type 53 sliders, but they still have a bowl and floats. Right? I think the bowls have a drain plug on the bottom of the bowl, but essentially the rest is the same with respect to running out the fuel from the bowls.

Good call on the warm up before sync. It made a huge difference on my bike during my learning curve trying to figure it out. A 10 mile loop did the trick.

[mneblett]

I have started doing that too. We'll see how it works on the new white floats I installed today. While I have everyone's attention, I have another question. The specs in the clymer manual say the floats should be 10 grams. The old ones were 14 and 15 grams each and were original bing floats. The new ones are 12 grams each. Should they be shaved down on top to bring them down to 10? Sounds crazy, but I am trying to minimize flooding/leaking and I really need to have these carbs running smoother.
That would be counter-productive.

The idea was to have floats with X grams in Y volume -- i.e., a desired low density so that their bouyancy exerts sufficient force to maintain the float bowl inlet needle against its seat. Shaving the floats lowers their weight, but also their volume -- no net change in density, but lower bouyancy (less volume displaced, less force holding up the needle).

My experience (FWIW) is that two grams is not critical, or even significant. It is far more important to keep the float needle seat free of crud. I'd wager that 90+% of float bowl overflows are caused by crud at the seat -- a reasonably fresh float (one that has not absorbed so much fuel that it is no longer sufficiently bouyant) adjusted anywhere near the proper parallel seating will not overflow in the absense of crud (or the bike laying on its side). A clean tank, intact petcock screens, maybe (strong pro/con opinions on this) in-hose fuel filters of a reliable/proven style, and periodic replacement of the float needle when excessively worn, will address virtually all Bing dribbles.

[Raceydog]

Geez, what a lot of haggling over nothing!
:fight

RELAX. Your bike is ok.:banghead

In the first place, float height is NOT THAT CRITICAL. Within reason is fine, no need to beat the thing down to the last .001".

The ethanol problem isn't that severe- I've seen saturated floats, of course, but not on every bike that comes through the door. Fuels vary, some are pretty snotty, most are ok.

Ethanol saturation doesn't become a problem til the float is significantly heavier than a new float, and begins to sit lower in the fuel. New floats weigh, IIRR, 10 grams. Worried? Weigh the floats. Or save your time worry and just replace them every couple years. They're cheap- are you?

Don't gas up at Discount Petrobarf. Don't add every available solvent fuel additive, that's just asking for trouble. Coating the floats with anything will make them heavier a lot faster than ethanol.....and if the stuff flakes/drools off, you have a new problem.

Ethanol-proof floats are great, but you're still gonna be into those carbs every year or so- airhead CV's need o-rings pretty regularly, and diaphragms every couple/3 years too. They're not maintenence free, and they're not gonna be. Live with it. That's why they made the bowls come off so easy.

I've installed the independent Bing floats for others, without any great problems; never used them myself, because it seemed a lot of money for.....well, nothing. I replaced my floats once in a while and never had any problems with them.

It's a smart practice to shut off the gas when you stop. The overflow stand tube in the float bowl is tiny- if you have a major float valve leak, it can still fill the cylinder just fine, while the overflow tube is draining full tilt. The tube isn't big enough to be a 100% solution. Besides, gasoline is....um.....flammable? Do you want a puddle of the stuff under your scoot, waiting for some moron with a cigarette?

I don't recommend shutting the gas off before you stop. (really? you really do that?) What if it stalls right before the semi changes lanes?

I've been draining and re-soldering cracked brass floats for....40 years? I don't see any more of them now than I remember seeing in the past, so it's hard to attribute a sudden rash of them to ethanol. I think they just crack from thermal stress over time- the brass is pretty thin. I mean, it's a float- and brass normally doesn't, so......

Who came up with ethanol? As usual, some well-intentioned, misinformed, smiling bobblehead in DC.
Politicians like it- another smiling baby to kiss, and a chip they can throw to those pesky environmentalists.
Gas retailers like it- they get to sell more gas. Ever check your mileage on gas vs ethanol?
Farmers love it- quadrupled the market price of feed corn overnight. Used to be a trash crop!
Rough on the water, though- corn farming is nitrate-intensive, and most of the nitrates applied wind up as runoff. Fish don't like it much. I hear there's a 600-square-mile dead zone at the mouth of the Mississippi........oh well. It's always something.

:violin


Want to haggle over something useful you can do for your Bings? Find a way to keep blow-by oil mist out of your idle circuit. Figure out what to use instead of a cold-start valve cover gasket.

Tune in next week for another episode of "As the Airhead Turns".........


Remember- it's not really rocket science til it gets past the clouds, no matter what they call it.

:wave

But if you're a real BMW perfectionist, I've got one last pair of titanium-plated Bing floats that Tom Cutter and I made in his basement back in the '80s, that I could let go for $300.

Each. :brad


YMMV!

wow. just wow.

[Raceydog]

That would be counter-productive.

The idea was to have floats with X grams in Y volume -- i.e., a desired low density so that their bouyancy exerts sufficient force to maintain the float bowl inlet needle against its seat. Shaving the floats lowers their weight, but also their volume -- no net change in density, but lower bouyancy (less volume displaced, less force holding up the needle).

My experience (FWIW) is that two grams is not critical, or even significant. It is far more important to keep the float needle seat free of crud. I'd wager that 90+% of float bowl overflows are caused by crud at the seat -- a reasonably fresh float (one that has not absorbed so much fuel that it is no longer sufficiently bouyant) adjusted anywhere near the proper parallel seating will not overflow in the absense of crud (or the bike laying on its side). A clean tank, intact petcock screens, maybe (strong pro/con opinions on this) in-hose fuel filters of a reliable/proven style, and periodic replacement of the float needle when excessively worn, will address virtually all Bing dribbles.
I agree with the buoyancy and weight statements totally. I would only shave weight on the part of the floats that didn't sit in fuel anyway which wouldn't affect the volume/displacement As far as the weight difference goes, if the spec for the float weight is supposed to be 10 grams and the new ones are 12 grams, that's 20% heavier. Two grams doesn't sound like much, but 20% does.
As far as a clean carburetor. The bike is a 13k mile bike that sat for 10 years with no fuel in the bowls. They were rebuilt, syncd, cleaned, etc... The left one still leaked. It was the one with the 15g float. That's 50% heavier. I just spent another 350 bucks to have them cleaned again because of a mysterious substance (probably the braided fuel lines being eaten away by ethanol). That sounds like a lot I know. New petcocks and screens. New needles. New gaskets etc.
The left one is still leaking after sitting still overnight. But a lot less than normal. That is why I came to the conclusion that the difference in the weight of the old one and the new one was affecting the buoyancy of the floats and the position of the float valve. I will adjust the tabs tomorrow. I didn't have time to take them off yesterday.
Thank you for your input. A few of the other replies were really negative and unhelpful.

[Raceydog]

I had some other thoughts about this, but then I see you are running an R50/5. A lot of the info and responses here will be based on the Bing CV's, which you do not have.
So my only suggestions which might be useful for your specific carbs would be;
Clean the carbs
Replace fuel line with something less sensitive to alcohol - found that braided looking fuel line from the dealer really leaches out from the alcohol - leaving black goo in the carbs
Take the bike for a 15 minute ride before attempting carb synchronization. Garage warmup doesn't cut it.

hopefully someone running slide carbs will have some other info for you.....

What type fuel line would you suggest? I had some clear fuel line on it before I took it to the mechanic who put the braided lines on.

[Raceydog]

+1 on a lot of fuss over nothing really. Shaving your floats to make your carbs run smoother? Ain't gunna happen IMO.

Those specs are akin to a speed limit sign or the line on a shot glass--technically those are the rules, but in reality they are only estimates/guidelines. Your o-rings, jets, cleanliness of the fuel circuit and balancing will help your road tractor run smoother.

I didn't intend to imply that making the float weight match what I read as spec would make them run smoother. I just want to try to eliminate fuel leaking in my garage by possibly making the floats actually shut off fuel flow. My wife is really worried about the gas smell.

[Raceydog]

I've not heard of this spec...I see no reason to modify brand new floats. Snowbum did some testing on a number of new/used floats:

http://bmwmotorcycletech.info/bingcv.htm

Just clean your carb and passageways, set the carb up properly, and there should be no real problems with leaking. They really do work fine.

I have the Type 53 carbs on a R50/5. Carbs have just been totally gone through again. I found the specs in the large Clymer book. Could be accurate. Maybe not. Thanks for the link.

[Raceydog]

Some of you guys may think it sounds stupid to suggest shaving the floats to make them match spec (correct spec or not) but until someone tests it, how can anyone be certain. What if it works great and becomes a standard fix in the future. Maybe the process could be named after me.

This thread was about ethanol affecting the floats. It doesn't eat them away apparently, so we must be talking about the weight of them. Otherwise, why are we even discussing it.

Doesn't it make sense to correct the weight of new floats if we are so concerned about the weight/buoyancy of ethanol soaked floats. :thumb

[jforgo]

What type fuel line would you suggest? I had some clear fuel line on it before I took it to the mechanic who put the braided lines on.

I got some gray stuff from an independent shop here "tridon" I think

[jforgo]

I didn't intend to imply that making the float weight match what I read as spec would make them run smoother. I just want to try to eliminate fuel leaking in my garage by possibly making the floats actually shut off fuel flow. My wife is really worried about the gas smell.

I am showing a float needle # 1311 254 767. That is what shuts the fuel from the lines off from the bowl. That may be your problem. I replace these along with the floats on my CV's.
I turn fuel off for my r100's about 3/4 mile away from home. Leaves just a bit in the bowls - I sometimes sputter in. I do this more to spare the floats - but I can see where it keeps crud from settling on the float needle.

[Raceydog]

I have type 53 carbs. The float needles are new and the carbs were cleaned.

I have been starting to cut the fuel off when I turn onto my street. I live in a neighborhood with plenty of room to get out of the way if I don't make it for some reason. (That last part is for the guys that think it is dangerous and that I might get run over by a big truck or something)

I will check out that fuel line. Thank you.

[jforgo]

I have type 53 carbs. The float needles are new and the carbs were cleaned.

I have been starting to cut the fuel off when I turn onto my street. I live in a neighborhood with plenty of room to get out of the way if I don't make it for some reason. (That last part is for the guys that think it is dangerous and that I might get run over by a big truck or something)

I will check out that fuel line. Thank you.

According to Bob's, that needle part # is for the type 53. Do these type 53 have separate needle seats, pressed into the body? ? I have heard these can crack and leak.

[Manfred]

Ethanol-proof floats are great, but you're still gonna be into those carbs every year or so- airhead CV's need o-rings pretty regularly, and diaphragms every couple/3 years too. They're not maintenence free, and they're not gonna be. Live with it. That's why they made the bowls come off so easy.

Each. :brad


YMMV!

I've seen a few others on this forum state that diaphragms on Bings need to be replaced every 3 or so years. Really? I recently owned a 1980 Yamaha XS850 with much hated Hitachi CV carbs and the original diaphragms were in them. Once in while a diaphragm will develop pin holes, or it might be torn while removing. But I've never had a Japanese bike that required - or had recommended - replacing diaphragms as a routine matter.

This is curious.

[20774]

I don't replace the diaphragms on my /7 in a routine manner, only if a problem develops or it's sufficiently long that I don't remember when last doing it. I keep records so could check that, but generally I only do it only when necessary. Besides getting pinholes, they can harden over time, resulting in poorer performance. So there may be something for replacing them on a bit more routine basis... :dunno ...

[carlo]

I don't replace the diaphragms on my /7 in a routine manner, only if a problem develops or it's sufficiently long that I don't remember when last doing it. I keep records so could check that, but generally I only do it only when necessary. Besides getting pinholes, they can harden over time, resulting in poorer performance. So there may be something for replacing them on a bit more routine basis... :dunno ...

I've replaced one diaphragm on my R100RT in 10 years. It got torn when a slide stuck at the bottom of its travel. The one I haven't yet replaced doesn't appear to have hardened noticeably. Since I purchased a pair of them, I now have a fresh spare to use if I need one.

I don't know how old the diaphragms were when I bought the bike, but given all the work I had to do on the bike when I got it, I'm assuming the PO hadn't looked at them in years.