Throttle cable question.

[Leo]

Hi All,

Has anyone fitted the split throttle cables to a '96 R1100RT. Are they better than the crossover style and is it a good idea or am I barking up the wrong tree.

[Mike T]

The split cable is better than the cross over cable but I think it would be very hard to retrofit this on your bike. You'll need to add the distribution box and even the throttle bodies have a different cam on them where the cable hooks into.

 

Others may have more insight on this but I think you would have to replace the throttle bodies to get it to work.

[Jameseo]

Why is it that you feel the split cable is better? The topside of the distribution box is not sealed and allows the internals to become filthy with dust and dirt which eventually inhibits the fast idle from functioning. The original system in '96 was simple and effective.

[steptoe]

Why is it that you feel the split cable is better? The topside of the distribution box is not sealed and allows the internals to become filthy with dust and dirt which eventually inhibits the fast idle from functioning. The original system in '96 was simple and effective.

 

Takes 20 minutes to clean the distribution box on a later bike.

 

Thats less than half the time it takes to attempt to try and balance the throttles on the early single cable bikes

[russell_bynum]

Why is it that you feel the split cable is better? The topside of the distribution box is not sealed and allows the internals to become filthy with dust and dirt which eventually inhibits the fast idle from functioning. The original system in '96 was simple and effective.

 

Takes 20 minutes to clean the distribution box on a later bike.

 

AFTER you've removed the belly pan, side fairings, and fuel tank to get to it, sure...it only takes 20 minutes.

 

OTOH, I've never heard of the junction box getting crudded up to the point that the fast idle doesn't work. (I'm having trouble even understanding how that would be possible.) The throttle action does get heavy when the stuff in there gets dirty, but it all still works.

 

I don't know which setup is better. I've only had the split-cable setup that came on the later bikes. I've heard from people who have had both...some say the old style was better/easier to work with, and some say the opposite.

[smiller]

Thats less than half the time it takes to attempt to try and balance the throttles on the early single cable bikes

BS. There is no demonstrable difference in sync reliability between the two schemes, and if I had to vote on anecdotal experience I say the earlier system is easier to work with and maintains sync longer.

 

The junction box added nothing but additional complexity, maintenance, and an additional point of failure... along with a tendency to break cables and mess up the fast idle system. The earlier system had none of these maladies.

[russell_bynum]

along a the tendency to break cables and mess up the fast idle system

 

About the fast idle...you're talking about the "My fast idle doesn't work after a TB sync" problem due to excessive slack in the short cables, right?

[smiller]

About the fast idle...you're talking about the "My fast idle doesn't work after a TB sync" problem due to excessive slack in the short cables, right?

I guess I'm talking about for whatever reason they fail or require additional attention when it's related to the junction box design, as I believe is often the case. In any event such problems are very rare with the earlier setup, in fact my fast idle adjustment hasn't been touched once since it left Germany 11 years ago and I think this the norm with the early bikes.

[russell_bynum]

About the fast idle...you're talking about the "My fast idle doesn't work after a TB sync" problem due to excessive slack in the short cables, right?

I guess I'm talking about for whatever reason they fail or require additional attention when it's related to the junction box design, as I believe is often the case. In any event such problems are very rare with the earlier setup, in fact my fast idle adjustment hasn't been touched once since it left Germany 11 years ago and I think this the norm with the early bikes.

 

OK.

 

I've heard of plenty of issues with the fast idle failing to work after a TB sync or cable replacement because of too much slack in the short cables, but I hadn't heard of a case of the box getting crudded up to the extent that the fast idle stopped working. I just wanted to understand which problem you were talking about.

 

I've never tuned one of the old style bikes, but the junction box design is definitely pretty fidgety.

[Jameseo]

I am not referring to the "My fast idle doesn't work after a TB sync"... I am referring to the "My fast idle doesn't work period"

Please see the attached image of my distribution block...

The end of the fast-idle cable that enters from the front (top in the image) left attaches to a black plastic slide. When the fast idle is engaged, it pulls the slide leftward while compressing the spring and rotating the central wheel which brings up the idle. Once the fast idle is disengaged the cable slackens and the spring reverses the function. In my case, the dirt creates enough friction that the slide will no longer return to the disengaged position by the force of the spring.

I have actually only tried to repair it once due to the PITA of removing it. Obviously, I didn't want to use a spray lubricant that would attract more dirt in the future - so I used graphite. The action seemed good for a while but that was short lived. The graphite probably just seeped out in the same fashion that the dirt seeped in.

When I purchased the bike the fast idle didn't work, at 18k miles. I now have about 45k and since no other functions of the throttle are compromised I have learned to live without it.

Leo,

I'm not sure if this problem plagues others but I've seen the '96 throttle linkage and would trade in a second.

[russell_bynum]

Right...I'm quite familiar with how the junction box works.

 

I guess I've just never heard of one getting gunked up enough that the fast idle would stick in the "on" position like that. FWIW, I never used any lubricant of any kind in there.

 

So...on your bike...if the fast idle is stuck "on", how do you prevent the bike from idling way too high?

[steptoe]

BS. There is no demonstrable difference in sync reliability between the two schemes, and if I had to vote on anecdotal experience I say the earlier system is easier to work with and maintains sync longer.

 

The junction box added nothing but additional complexity, maintenance, and an additional point of failure... along a the tendency to break cables and mess up the fast idle system. The earlier system had none of these maladies.

 

I have my own independent BMW business, and work on these bikes all day every day. Every type of bike. I assume you just have experience of working on your own bike ?

 

The early throttle set up is far far harder to sync correctly than the later type.

 

You can get them approximately as easy as the later type ( which may suit a lot of DIY'ers, but i can't run a business on a "near enough" basis ). But to get them spot on takes more time. Plus i see more broken cables on the early type than the later type. And thats fact, not guess work assumption.

[Wooster]

...So...on your bike...if the fast idle is stuck "on", how do you prevent the bike from idling way too high?

 

One twist of the throttle and the fast idol lever returns to normal. Note - When the lever and cable 'hang-up', the horizonatal wheel in the bowden box isn't affected, only fast idyl's (neat oxymoron) cable's plastic slide.

As you may assume, my '98 RT is afflicted with this picadillo yet unlike Jameseo, I wouldn't trade my bike for anything (OK, maybe a '07 GS with LeeAnn Tweeden on the back).

 

Wooster who thinks his countrymen are lazy enough w/o tv show searching for American idylls

 

On second thought, I'm not sure if bowden's wheel is unaffected when fast idle lever hangs up; I've stopped using lever a year ago. I'm certain of quick fix, i.e., twist grip and all is well.

[Ken H.]

In my case, the dirt creates enough friction that the slide will no longer return to the disengaged position by the force of the spring.

When the Bowden box gets to the point where the fast idle slider won't reliably return, the only long term solution I know of is a new box. It's not that expensive as far as BMW part go.

 

And let me assure you, despite it's simplicity of appearance, you don't want to lust for the 1996 design.

[smiller]

Plus i see more broken cables on the early type than the later type.

That is directly contrary to reports on the forum. Every report of broken throttle cables I've seen is for a '97 or later bike. That could well be because there are so many more of these (although I think the relationship to the problem and the junction box is pretty clear.) OTOH you are saying that in spite of the much smaller number of early bikes you actually see more failures with these? Hmmm. What type of failures are you seeing with the older system? Where is the break occurring? I'm interested because this is the first I've ever heard of it.

 

I assume you just have experience of working on your own bike ?

You assume incorrectly.

 

And let me assure you, despite it's simplicity of appearance, you don't want to lust for the 1996 design.

What experience leads you to say that?

[Jameseo]

...yet unlike Jameseo, I wouldn't trade my bike for anything (OK, maybe a '07 GS with LeeAnn Tweeden on the back).

 

Let me just clarify that I, neither, would trade my bike for anything (despite all of the BMW idiosyncrasies I have addressed in my three years of ownership.) I was simply stating that I wouldn't mind trading the throttle system. Let me also second the GS/Tweeden notion.

However, given Steptoe's input, I might think twice. Although it seems that I have greater difficulty syncing mine than Seth does with his '96.

Perhaps, as Ken noted, the only real solution is to replace the box. Maybe that would address my syncing troubles as well. I'll have a look at what the "It's not that expensive as far as BMW part go" actually means.

[steptoe]

[quote What type of failures are you seeing with the older system? Where is the break occurring? I'm interested because this is the first I've ever heard of it.

 

 

The cables fray. Usually just before it gets to the L/H throttle body .

[Ken H.]

The challenge of the '96 design is the rotation of the right side TB is reliant on the rotation of the left side. If a particular bike's sync situation is such that requires the right side to begin opening before the left, it is almost impossible to obtain, as the rotation of the left side has not yet begun.

[smiller]

OK, interesting comments from all. But given that the simple and reliable system on my bike has worked flawlessly for 90k miles I'm still not quite convinced that I would be better off with the junction box mess that seems to generate a host of complaints with no real benefit in return.

 

But hey, I also can't see why one would replace a simple and reliable cable-operated clutch with a hydraulic system that seems to cause all sorts of mayhem or replace a low-maintenance brake system with two-finger stopping power with a complex servo system so I can have non-linear one-finger stopping power... but then again I'm often accused of having a strange outlook on things.