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JimmR75

Throttle cables

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JimmR75

I am continuing to sort out my recently acquired 97 R1100RT with 80k on it.  The choke / fast idle was inop when I acquired it and I attempted adjusting the cable at the control lever on the bars.  I believe my efforts have caused "issues" in the bowden box. 

 

The adjustment had minimal effect on the idle but has resulted in a "hanging throttle" when the bike is cold.  By this I mean that it starts and runs normally but when cold the engine "hangs" at rpm when I roll the throttle closed.  I have checked the throttles at the throttle bodies and they snap closed normally when opened by turning them open individually by hand and releasing them.  However, if I open the throttle by hand and release the grip, they close slowly.  

 

I suspect the bowden box is either the issue or where the issue lies.  I anticipate needing a fast idle cable at a minimum but will know more once I remove the bowden box.  I have watched the videos of this process and am prepared for the "fiddling " required.  

 

I am looking for recommendations for a source for cables and any other input from those more experienced than I at this particular project.

 

Thanks in advance for any input or replies.

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dirtrider
37 minutes ago, JimmR75 said:

I am continuing to sort out my recently acquired 97 R1100RT with 80k on it.  The choke / fast idle was inop when I acquired it and I attempted adjusting the cable at the control lever on the bars.  I believe my efforts have caused "issues" in the bowden box. 

 

The adjustment had minimal effect on the idle but has resulted in a "hanging throttle" when the bike is cold.  By this I mean that it starts and runs normally but when cold the engine "hangs" at rpm when I roll the throttle closed.  I have checked the throttles at the throttle bodies and they snap closed normally when opened by turning them open individually by hand and releasing them.  However, if I open the throttle by hand and release the grip, they close slowly.  

 

I suspect the bowden box is either the issue or where the issue lies.  I anticipate needing a fast idle cable at a minimum but will know more once I remove the bowden box.  I have watched the videos of this process and am prepared for the "fiddling " required.  

 

I am looking for recommendations for a source for cables and any other input from those more experienced than I at this particular project.

 

Thanks in advance for any input or replies.

 

Afternoon JimmR75

 

No hanging throttle BEFORE choke cable adjustment // problem with hanging throttle AFTER choke cable adjustment--

 

Put your choke cable adjustment back to where it was before the problem then start over.

 

If the lower (short) throttle cables are not initially set correctly then an incorrect  choke cable adjustment can foul up the cable action.  

 

Go by the BMW manual & set the main (upper) cable & lower cables correctly THEN work with the choke cable. 

 

 

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Jim Moore

The problem with an "inop fast idle" is normally not the fast idle cable itself. It's the fact that the lower throttle cables have stretched over time and now have too much slack. I would try undoing whatever you did to the fast idle cable, then do a throttle body synch, focusing on removing nearly all the slack from the lower cables.  

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Still CAL

I bought the same model RT last summer and when I went to get new throttle and fast idle cables I ran into what seems to be a mid-year changeover issue. Euromotoelectrics.com (EME) did not have the correct part # 30 on the fiche for this bike, but Bikebandit.com does. It's the main accelerator cable from the throttle to the Bowden box, part #32737659691

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JimmR75

Thanks very much for the replies.  I have done a throttle body balance and understand the cable issues.  The factor that makes me suspect the bowden box is the heat component. 

Once warmed up the throttle behaves normally. 

Only when cold does it hang, 

The butterflies snap back properly when cold.  

 

This make me believe that something that was moved in the bowden box is hanging when cold and freeing up once absorbing engine heat.  If nothing else I'm going to pull it out, lubricate and reassemble, and do another TB balance.

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dirtrider
7 minutes ago, JimmR75 said:

Thanks very much for the replies.  I have done a throttle body balance and understand the cable issues.  The factor that makes me suspect the bowden box is the heat component. 

Once warmed up the throttle behaves normally. 

Only when cold does it hang, 

The butterflies snap back properly when cold.  

 

This make me believe that something that was moved in the bowden box is hanging when cold and freeing up once absorbing engine heat.  If nothing else I'm going to pull it out, lubricate and reassemble, and do another TB balance.

 

Afternoon JimmR75

 

You say that it acts up cold?

 

Are you using your grip heaters? If so those have a long standing habit of making the twist grip stick if the handlebar weight clearance isn't set with a large enough gap.  

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JimmR75

DR, no grip heaters on this RT.  The "hanging throttle" occurs only until the bike warms up.  My guess at this point is that when I initially adjusted the fast idle cable at the bar lever it moved the slide inside the bowden box to a space it had not been in before, producing a hanging or sticky throttle.  Once the bike warms up it behaves normally which I speculate is due to the box absorbing heat and changing just enough to allow things to slide and move again.  

 

This is all speculation but my plan is to pull the box, clean and lubricate, and change cables if I can find them at a reasonable price.  The prices that I am finding are not reasonable so I continue to shop before removing the box, which looks like a genuine PIA.

 

I also own a 95 R1100RSL with the crossover cable.  I understand why BMW went away from that but it sure looks like a split throttle cable would have been a much simpler solution.

 

 

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AndyS

Seems like an obvious thing, but have you double checked all the cable routings. Maybe cable ties in wrong place or too tight. Are the cables getting trapped when the thank goes back on. etc.

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dirtrider
50 minutes ago, JimmR75 said:

My guess at this point is that when I initially adjusted the fast idle cable at the bar lever it moved the slide inside the bowden box to a space it had not been in before, producing a hanging or sticky throttle.  Once the bike warms up it behaves normally which I speculate is due to the box absorbing heat and changing just enough to allow things to slide and move again.  

 

 

 

 

 

 

Morning JimmR75

 

This is easy enough to prove out, just don't use the choke for initial cold start. If that eliminates the cold hanging throttle then you might be on to something.

 

If the throttle still hangs up cold then it can't be the choke slider wedge in the bowden box as you didn't move it. 

 

 

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JimmR75

DR, excellent point.

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