Vintage BMW Motorcycle Owners

So I had a leaky Bing, first option is replace the float bowl gasket, right, as that usually stops the leak?
Well not this time.

So I backed off from this plan and thought about it: take one step at a time in a very methodical approach.

So I took the float bowl off and set it on my workbench in a steel bowl, then added about 3/8 of an inch of gas and let it sit. Voila, gas was leaking from the bowl!

So I determined from this trial that gas was likely leaking past the brass stand pipe although it was not detectable to the eye.

Then I obtained another float bowl and tried this experiment again; no leak! That was good.

Then I installed the float bowl on the carb and let the bike sit for a long period of time with both petcocks set to reserve. No leaks, so problem was resolved.

Learning, learning, and success. I learned to be more methodical, I hope!

Nice to find a solution! What carb and bike are you talking about?

Hey Mac, let me get this straight, you found the float bowl itself was leaking, perhaps the brass choke tube? I must admit, this is the first time I have ever heard or seen it happen.

Good catch!

Man, that would have driven me crazy because I would have been setting and resetting float levels, changing gaskets. Since I have never heard of a float bowl going bad, I would never have thought to do what you did. Cheers, St.

Chasing a leaking carb, I finally discovered that the overflow tube in the float bowl had a tiny crack in it that
was letting fuel weep out. I discovered this by filling the bowl with fuel off the bike. I talked to the people at Bing and they told me that it is pretty common on the older bikes. I am replacing both bowls on my /6. They are available from most BMW dealers as well as directly from Bing. The price at dealers is always a little bit less. I paid about $55 at Hermy's BMW in Port Clinton PA.

It has been a while but i used to be able to repair those by pulling the overflow tube out of the bowl and CAREFULLY JB welding in a replacement piece of tube from hobby store. Put the JB on the OUTSIDE of the tube before inserting in hole - don't put the epoxy in the hole. I have also seen riders slide a piece of tight fitting fuel line over the tube to temporarily/permanently fix a leak.