The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: clouseau on July 02, 2009, 09:57:01 AM

Title: Is this normal?
Post by: clouseau on July 02, 2009, 09:57:01 AM

When coming to an abrupt stop or a normal stop down a hill with clutch engaged, the bike wants to die or will die (not hold idle). I can sense when this will happen and just blip the throttle to prevent it from dying but it is annoying.
I've double checked the floats, which are new.
Is it that the fuel in the bowls is flooding the engine or the other way around?

Title: Re: Is this normal?
Post by: montmil on July 02, 2009, 02:06:39 PM

If you suspect the floats are a part of your issue, I'd certainly do a careful inspection to see that they are set properly. Did you adjust the new ones as you installed them? Did this idle problem manifest itself prior to the float replacement? Throttle cables adjusted correctly? Are the carbs sitting "vertical" as installed... may be a float dragging against the bowl's interior.

I'd also suggest you check the float needle and it's seat. May have some garbage that's holding it open a bit.

Have you adjusted the Idle Air Mixture Screws lately? You may consider building your own $5.00 carb synchronizing stick and tuning those carbs just right.

Post up what you discover.    Monte

Title: Re: Is this normal?
Post by: Barry on July 03, 2009, 12:48:56 PM

It could be an idle mixture problem either the mixture screw setting or a partial blockage of the idle passages. There are 2 very small holes close to the throttle plate. Both are part of the idle circuit one is controlled by the mixture screw setting and the other is effectively an open passage from the idle jet.  I would check both are clear.

Title: Re: Is this normal?
Post by: Barry on July 03, 2009, 01:59:04 PM

I should have added to check the idle jet as well. It would be no use having the those 2 idle ports clear if the idle jet itself was partially blocked.

This diagram illustrates the location and function of the idle ports nicely.


(http://)

Title: Re: Is this normal?
Post by: Justin B. on July 03, 2009, 07:29:23 PM

Nice diagram...

Title: Re: Is this normal?
Post by: Bob_Roller on July 03, 2009, 07:54:27 PM

Barry,

Do you have any other diagrams of the other circuits for the Bing carburetors ?

Title: Re: Is this normal?
Post by: montmil on July 04, 2009, 09:41:47 AM

Here's a page with additional carb / fuel flow drawings. Justin's link on another thread was worth searching through.  [smiley=thumbup.gif]

http://www.stephenbottcher.net/BMW/jetting.htm

Monte

Title: Re: Is this normal?
Post by: Justin B. on July 04, 2009, 10:47:50 AM

Stephen's got a lot of neat stuff hid there!  I was at one of the Boxerworks Rallys when Stephen pulled in on his GS with a spare tire lashed to the back!  Rode all the way from Ontario...

Title: Re: Is this normal?
Post by: Barry on July 04, 2009, 12:17:32 PM

That was the best diagram I could find to illustrate the idle circuit and none of you spotted it's not actually a Bing CV.  

I have to own up it came from a Harley web site.

It's identical in principle and very close in construction to a Bing CV though so it does the job.

I'll see if there are any other diagrams we can borrow.

Title: Re: Is this normal?
Post by: Barry on July 04, 2009, 12:57:20 PM

This is the next diagram showing the main circuit. It's not as good as the first.
(http://)

Title: Re: Is this normal?
Post by: montmil on July 04, 2009, 06:30:39 PM

Quote

...and none of you spotted it's not actually a Bing CV.

Good Lord. Is this a test? [smiley=deal2.gif]

Title: Re: Is this normal?
Post by: Justin B. on July 04, 2009, 09:31:56 PM

It's a Stromberg or Zenith?

Title: Re: Is this normal?
Post by: Barry on July 05, 2009, 04:23:10 AM

No not a test !  I was just glad I got away with it.

To be honest I didn't know what it was without checking. I think it's supposed to be a Keihin