Forum bmwbike.com

I have just finished repacing all gaskets and jets etc including new slides on my R69S. All new parts are according to Bing specs. The needle was put in the #2 position (second from top) and the air adjustment screw was turned 2 turns from end as a start. When I turned the tap on, I started getting petrol leaking from the idle air guide on both carbs. From the schematics, there are no gaskets in this area to be placed. I took the slides out and looked inside. There is no petrol overflow trickling down through the little hole at bottom of chamber and still the leak continues.....is there a connection in the carb block somewhere that is causing this ingress of fluid?

Could the leak be caused by the float needles? When the float chamber is full of gas, the top of the needle rises up and cuts off the gas. If the needle or seat is worn, gas can leak. Bing makes new lever tops for their carbs, in which the float transfers its bouyant force to a lever which holds a small rubber tipped needle, which makes a better seal.

Thanks Allen. I have come to the same conclusion by openning the two carbs and looking inside with the slides removed. The float needle contact with the chamber cover does not provide a good seal and causes the petrol to overflow and enter the air needle orifice. I think what happened is that I interchanged the top from an R50 at some point and sold the other. The R50 covers must of had defective seatings with the float needle point. So I have ordered direct from Bing the proper float needle and corresponding lever top. Thanks for the advice.

Pierre

Hi Pierre

The new tops complete with needle valve etc. that Allan spoke about have the number 13 11 1 252 176. In addition, you will also need a new guide needle which replaces the old float needle. Part no. is 13 11 1 252 178, and a small washer that goes over the guide needle and rests ontop of the float has the number 13 11 1 252 179.

Best regards,

Mark
Mark Huggett GmbH

Thanks Mark, you caught me just in time as I was about to press th order button......now that's what I call customer survice and taking care of business!

Pierre