floats

Hi Me again, while doing some maintence I noted the floats on my alcohol proof bing carb kit ,dont float as they used to so, I still have the original floats how do these stand up with todays fuel? once again thanks in advance Jimmy

I had problems with the floats on both of my Airheads, as well as other carb parts. I now run the bikes with only non-ethanol gas and have had no problems since. If it’s available to you, that’s what I would recommend

My suggestion

I would look for a replacement set of alcohol resistant floats to replace the bad ones. I would not go back to the original floats.

I am not an expert on floats, early BMW floats were not alcohol resistant, later year floats may have been or were.


I also run non-ethanol gas WHEN I can find it. I also run the highest octane 10% gas.

The bikes had been converted over to alcohol resistant floats and rebuilt with alcohol resistant parts and fuel lines.

Both my airheads run fine on either gas. I will not run any mix higher than 10%, however. St.

carb floats

Hello again, i was wondering how long the std floats would last ? Jimmy

jimwjarmour said:

Hello again, i was wondering how long the std floats would last ? Jimmy

Click to expand...

Hi Jimmy,

I use the standard floats. To test if they are "fuel logged", weight them on a kitchen scale that can measure in grams. New floats are on the order of 10-13 grams. Fuel logged floats are on the order of 18+ grams.

I have standard floats that have been used for more than 5 years with Ethanol (10%) laced gasoline. They are not fuel logged. That said, the rubber seals in the carbs don't seem to hold up as long as I would like.

My general rule of thumb is to consider replacing the carburetor o-rings and floats in the 5-7 year bracket to avoid unpleasant experiences. It's easy to check the o-ring condition by unscrewing the jet carrier with the large o-ring and the idle jet screw with the small o-ring. It they tear when you remove them, seem swollen, or are cracked, time to replace them, the diaphragm, and the floats while you are at it, aka, a full carburetor rebuild. That will cost you about $250-$300 at today's parts prices and using your own labor.

Here is how you do a complete rebuild.

• 13 BMW 1973 R75/5 Rebuild & Refinish Bing Type 64/32 Carburetors & Karcoma Petcocks
• 13 BMW 1977 R100RS Rebuild & Refinish Bing Type 94/40 Carburetors

At about 35,000-45,000 miles, it's worth replacing the jet needle and needle jets as well. These wear from vibration and lose the ability to accurately meter the mid-range fuel flow.

I hope that helps.

Best.
Brook Reams.

thanks for the help

thanks again yes I noted Motobins only has the standard items for sale, I installed 2 bing kits way back at an national rally Madison Indiana I seem to remember so they are a lot of years old, so being the packrat that I am I still have the old std ones from both mine and my friends bike ,so if they only last a year or two that will do, re the diaphrams O rings and needles all changed last year, so, at present I,m installing an RT fairing ,and once finished will try the old floats, thanks all, bye for now Jimmy