removing/installing diaphragms?

[georgesgiralt]

Hello !
I did change my diaphragms a little more than a year ago. I bought them from BMW 3 at a time because I like to have one in the spare box in case something goes wrong on a Saturday afternoon...
Last month a friend of mine asked for help on his carbs (he also own an R65)
I gave him a shopping list with 2 new diaphragms from BMW and, guess what ? theirs are stiffer than mine ! and wear the same part number. So I guess BMW has switched supplier or has fired the quality control department...
The bike runs fine (no comparison before and after.... if you saw what we find in the carbs...) so I wonder if it makes a lot of a difference.

[Rob Valdez 79 R65]

but for some reason, the right carb just kept loosen after a while...  

Did you replace the white rings with new, as well?

[AlfromNH]

AlfromNH, please keep us refreshed with your work on these flat tops...

I'll be happy to, although I won't be able to report anything about the performance until I get the bike together in the spring.

I'm assuming Bing was closed for the (US) holiday weekend, I hope to hear from them today.

[fbenach]

Hello Rob!!!

Yes, we did change the white ring... the left carb actually works perfect, but the right one kept loosing the diaphragm and we just gave up!!!

Now, I got a set of "hat-top" carbs very cheap, so I decided to work them out instead, but will be redoing my flats some day, just to have a spare...

[AlfromNH]

I ordered 1 white ring from Bing for $6.41. I also ordered the manual. I ordered jets and needles from the BMW dealer. BMW prices are cheaper than Bing's, which I found somewhat surprising.

[Tony Smith]

I gave him a shopping list with 2 new diaphragms from BMW and, guess what ? theirs are stiffer than mine ! and wear the same part number. So I guess BMW has switched supplier or has fired the quality control department...
The bike runs fine (no comparison before and after.... if you saw what we find in the carbs...) so I wonder if it makes a lot of a difference.

Absolutely none whatever. There is a surfeit of "power" available in the vacuum system of the carb. If you want to amuse yourself, calculate the area that is exposed to vacuum and then work on (for the sake of example) a pressure of 14psi. The diaphragm being a "bit stiff" is not going to stop that slide doing what it is supposed to do. And within sensible limits there will be no difference between the thickest aftermarket diaphragm and the one you knock up in an emergency out of a gossamer condom (but don't used the ribbed ones, you would not want your R65 to get excited).