The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Crossrodes on July 17, 2010, 05:33:15 PM

Title: Question re Replacing Diaphragm on Bing Carb
Post by: Crossrodes on July 17, 2010, 05:33:15 PM
I have a '79 with flat top Bing carbs.  It's shown on the parts fiche for my bike.  For the life of me I can't figure out how to remove and install the new diaphragm.  If anyone with a flat top carb has done this with this carb could you please tell me how I do this.  

The slider has what appears to be a big plastic "O ring" on top.  The inner part of the diaphragm sits under this "O Ring."  It appears that I somehow have to remove the "O ring" but it is held in place by what appears to be a collar that appears to be part of the slider body.  It may be that this collar is threaded inside but I can't move it.  

Anyone done this that has the answer?
Title: Re: Question re Replacing Diaphragm on Bing Carb
Post by: Bob_Roller on July 17, 2010, 05:42:36 PM
There's a plastic ring that needs to come off, to get the diaphragm off .

I think you need to warm the ring up with a hair dryer, or something similar, to make it a bit more pliable .

Rob Valdez has done this with his carbs, from what I can remember, the plastic ring is not widely available here in North America .

Hopefully he'll see this and get you the info you need .
Title: Re: Question re Replacing Diaphragm on Bing Carb
Post by: Crossrodes on July 17, 2010, 07:29:47 PM
Bob, from what you remember was Rob able to reuse the plastic ring after it was removed with heat?  I have to call Bing on Monday so if I need them I'll order them at that time....Believe it or not I found that I had no float needle in this carb.  How it ran I'll never know.  I don't recall any flooding problems and never smelled gas.
Title: Re: Question re Replacing Diaphragm on Bing Carb
Post by: Crossrodes on July 17, 2010, 07:41:25 PM
Bob, problem solved.  I decided to see if I could pry the plastic ring off with a large bladed screwdriver.  It popped right off...no heat required.  So then I fit the new diaphragm carefully and popped the ring back on using the palm of my hand...No problemo.

It's amazing what you can do with a little help from your friends.  Thanks Bob.

Mike
Title: Re: Question re Replacing Diaphragm on Bing Carb
Post by: Rob Valdez 79 R65 on July 20, 2010, 02:44:20 AM
Mike,

Sorry I didn't see this one till now.

You did right - pry it off.  I reused mine until one wouldn't stay in place any longer.  By then, Bing Agency USA was selling the rings.  You should call and buy a couple for the future.  They are not expensive.

The man at Bing suggested I boil the ring for a little while to make it go in place easier.  I did, but I don't think it made much difference.
Title: Re: Question re Replacing Diaphragm on Bing Carb
Post by: cephas1981 on July 21, 2010, 09:51:16 AM
Mike,

Just make sure you put the ring on so the smooth side is facing up.  This holds the diaphram in place more secure than the other way.  I learned the hard way when I started to hear a whistle and loss in power.  I found I had the plastic piece smooth side down and the diaphram wiggled out from underneath it allowing a leak.
Title: Re: Question re Replacing Diaphragm on Bing Carb
Post by: Rob Valdez 79 R65 on July 21, 2010, 04:26:14 PM
Quote
Mike,

Just make sure you put the ring on so the smooth side is facing up.  This holds the diaphram in place more secure than the other way.  I learned the hard way when I started to hear a whistle and loss in power.  I found I had the plastic piece smooth side down and the diaphram wiggled out from underneath it allowing a leak.

Old on left, new on right:

(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.pbase.com%2Ftomfarr%2Fimage%2F80793349%2Fmedium.jpg&hash=2b18be9299de03dad718266ce045e0507705ec34)

(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.pbase.com%2Ftomfarr%2Fimage%2F80793399%2Fmedium.jpg&hash=887129cb7b3de8fbf93ec35f46029ed836f04f4a)