Throttle body plumbing...

[spacewrench]

As I excavate my way to my transmission/clutch bolts, I'm trying to understand what I encounter so I can put it back right.  I've just found a hose that goes between nipples on the bottom of each throttle body, with a T in the middle that runs back to an electrified valve that I think was part of the evap cannister system (which was gone when I got the bike).  These nipples are shown capped off in the service manual.  My questions:

 

* Are the nipples where you'd connect vacuum gauges to balance the throttle bodies?

 

* If I cap them off, I think I can lose the T hoses and the electrified valve.  Any downside to that?  (I've read that some people put a resistor where the valve is, to fool the ECU into thinking the valve is still there?)

 

Bonus question:

 

My bike didn't have quick-disconnects on the fuel tank lines, but I'd like to add them.  However, there's not much horizontal space between the tank pipes and the fuel distributor inputs -- if I put in the disconnects, I think there's only room for very short hoses connecting everything, which will make it difficult to raise the tank enough to reach the QDs.  Do QD-equipped bikes have shorter fuel distributor pipes, shorter tank pipes, or loops of hose under the tank?  What's the standard way to plumb QDs into the circuits?

[szurszewski]

You can cap off the nipples. 
 

QDs - I would put them in the middle of the available section of hose - offset them from each other a bit so they stack in there better, and put them on in opposite directions so you can’t put the wrong hoses together. I usually cut out a small section of each hose so things stay the same length (as you said, not much room) but if you just cut each hose and splice in the QDs they will increase the overall length of each hose run a bit. 

[Jim Moore]

There's a K-bike part that people use to cap the nipples:  13 54 7 694 924

[dirtrider]

9 hours ago, spacewrench said:

As I excavate my way to my transmission/clutch bolts, I'm trying to understand what I encounter so I can put it back right.  I've just found a hose that goes between nipples on the bottom of each throttle body, with a T in the middle that runs back to an electrified valve that I think was part of the evap cannister system (which was gone when I got the bike).  These nipples are shown capped off in the service manual.  My questions:

 

* Are the nipples where you'd connect vacuum gauges to balance the throttle bodies?

 

* If I cap them off, I think I can lose the T hoses and the electrified valve.  Any downside to that?  (I've read that some people put a resistor where the valve is, to fool the ECU into thinking the valve is still there?)

 

Bonus question:

 

My bike didn't have quick-disconnects on the fuel tank lines, but I'd like to add them.  However, there's not much horizontal space between the tank pipes and the fuel distributor inputs -- if I put in the disconnects, I think there's only room for very short hoses connecting everything, which will make it difficult to raise the tank enough to reach the QDs.  Do QD-equipped bikes have shorter fuel distributor pipes, shorter tank pipes, or loops of hose under the tank?  What's the standard way to plumb QDs into the circuits?

 

Morning  spacewrench

 

What are you working on?

 

I believe that you have an 1100S? Is that the motorcycle that you are working on? 

 

In any case, if you don't include the year & model in your  thread heading, or in the text somewhere, then you can get back some incorrect info as most assume that you have an RT unless stated otherwise.

 

* Are the nipples where you'd connect vacuum gauges to balance the throttle bodies?-- Yes those are the nipples where you would attach your manometer or balance gauges.

 

* If I cap them off, I think I can lose the T hoses and the electrified valve.  Any downside to that?-- You can cap them off or just leave the hose between the TB nipples & cap off the open fitting on the Tee.  The OEM non-evap bikes came with those nipples capped off. You do get a little cross side balance equalization at idle if you leave the crossover-hose in place but on exposed throttle body bikes they look neater if you remove the hose plumbing.  

 

I've read that some people put a resistor where the valve is, to fool the ECU into thinking the valve is still there?-- No need for a resistor as the Motronic (ECU) only controls that circuit but has no way of monitoring it so has no idea that it is even gone.  Just remove the evap solenoid & tape the connector back (or just hide it). 

 

My bike didn't have quick-disconnects on the fuel tank lines, but I'd like to add them.  However, there's not much horizontal space between the tank pipes and the fuel distributor inputs -- if I put in the disconnects, I think there's only room for very short hoses connecting everything, which will make it difficult to raise the tank enough to reach the QDs.  Do QD-equipped bikes have shorter fuel distributor pipes, shorter tank pipes, or loops of hose under the tank?  What's the standard way to plumb QDs into the circuits?-- I can't add anything to what Szurszewski posted above except to say--  if you shop around you might be able to find shorter metal quick disconnects.  The BMW OEM  QD's are fairly long. 

 

 

 

[spacewrench]

Thanks szurszewski, Jim Moore & dirtrider!  This is indeed an R1100S; I forget that some people have more than one BMW.  Some even have BMW-branded caps on their throttle body nipples!  This project is going slowly, but I'm getting better at making sense of the various systems I encounter, matching them up to old threads on the 'net, and hopefully picking some of the knowledge an actual mechanic might not get until after the first time.

[Lowndes]

"My bike didn't have quick-disconnects on the fuel tank lines, but I'd like to add them.  However, there's not much horizontal space between the tank pipes and the fuel distributor inputs -- if I put in the disconnects, I think there's only room for very short hoses connecting everything, which will make it difficult to raise the tank enough to reach the QDs.  Do QD-equipped bikes have shorter fuel distributor pipes, shorter tank pipes, or loops of hose under the tank?  What's the standard way to plumb QDs into the circuits?"

 

Spacewrench,

 

I was able to install the brass QD's from Beemer Boneyard on my S, no problem.  https://www.beemerboneyard.com/cpcqkdiscon.html  You will thank yourself every time you have to remove the tank.

 

DO get the plated brass instead of the plastic.  

 

Install them in opposite directions so you can't get the lines crossed up and connect the fuel supply line to the return.  It runs better that way.

 

You might as well get the Oetiker style SS hose clamps.  They work much better than the screw type, ESPECIALLY inside the gas tank.  AMHIK.  https://www.amazon.com/Glarks-7-21mm-Stainless-Stepless-Pincers/dp/B073B32XLP/ref=sr_1_11?crid=3JFMVVKIDOANB&keywords=oetiker+clamps&qid=1585225754&sprefix=oetiker%2Caps%2C152&sr=8-11

 

Get familiar with how the release buttons on the QD's work before you install them.  Be sure to press AND HOLD the releae buttons before disconnecting AND CONNECTING the QD's.  The tiny O-ring seals will last much longer that way.  Carry the extra O-rings in your tool kit, too.

 

 

[spacewrench]

Inside of tank is cleaned up (new fuel filter, stainless steel U tube, new crimp-on clamps).  There is not much room in there!  Tomorrow night: quick disconnects and slash-cut vent tubes.