The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: R65TR6 on October 30, 2025, 01:24:09 PM

Title: Bing 32mm piston slide orientation
Post by: R65TR6 on October 30, 2025, 01:24:09 PM

Dumb question. Do the cut out arches on the slide go with the direction of the airflow, or 90 degrees from it??  I assume go with the flow, but some Bing diagrams show the piston turned 90 degrees.

Thanks

SR.

PS I bought my R65 new in 1986.  Still have it. 

Title: Re: Bing 32mm piston slide orientation
Post by: Barry on October 31, 2025, 04:06:39 AM

The cut outs on the bottom of the slide go with the flow and just as important is to get the slide the right way around. Look on the bottom of the slide and you will see a small hole that communicates the vacuum signal to the top of the diaphragm. The slide should be orientated so the hole is nearest the butterfly.

Title: Re: Bing 32mm piston slide orientation
Post by: R65TR6 on October 31, 2025, 05:19:36 AM

Thank you!

Title: Re: Bing 32mm piston slide orientation
Post by: georgesgiralt on October 31, 2025, 06:06:00 AM

Hello,
If your bings have a dome shaped top, the diaphragm has two notches, ont on the piston side, one on the body side which ensure you do not mess the orientation.
If your bings are the flat domed one, you "normally" can't mess the orientation because the diaphragms are not replaceable ... But if you are careful this can be done and, thus, you need to take extra care to respect the proper orientation of the piston in the body...
Hope this helps

Title: Re: Bing 32mm piston slide orientation
Post by: R65TR6 on October 31, 2025, 01:16:01 PM

Thanks.  Mine have no notches, but are now correctly oriented with vacuum holes on the butterfly side.  One carb now clean and assembled, one to go yet.

But now that you mention it, I was curious as to why there wasn’t an alignment notch.  Guess there are in some versions.