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Discussion Starter · #1 ·
I apologize for all these throttle body question
I have two more que (2011 rt)
1 what would cause the slack to change
2 after watching jvb clip on line it seems that to adjust the slack
You connect twin max or whatever to the vac lines then loosen lock nut and tighten until you get some movement on the gage then back off 1 full turn ...di both sides
am I understanding that correctly?

I've read on other threads that you should only adjust the right side to match the left, but if I adjust both success for slack then I've changed both the left and right sides...is that a problem??
Thanks for any help in understanding the process
 

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As I have taken on the maint on my '12 R1200RT, I plan on purchasing the Twinmax to ensure the two TB stay in sync - looks like a must. I can the see how I have been doing on my vintage 79 SX650 too :)
 

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I found some of the descriptions on adjusting throttle cable slack a little confusing. I had to actually do the TB sync before it became clearer. It's important that the throttle cables have some slack at idle to ensure that throttle bodies are not being held open by the cable. The instructions often state 1mm of slack. In practice though that really means a minimum of 1mm. During the TB sync you are attempting to have both TB's pulling the same vacuum at the syncing rpm. There is no specific target measurement. Syncing involves lengthening or shortening one throttle cable until both TB's are in sync. If you started the procedure with both cables having 1mm of slack, then you must add slack to one of the cables to achieve sync. This means that one side will have more slack than the other at idle. From my experience, only small adjustments are required. The reassuring thing about this process is that if you make small adjustments at a time to only one cable and have noted the amount of slack in each cable before you started, you can always set it back to the way it was when you started.
 

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Discussion Starter · #6 ·
According to jvb web site you adjust the slack st the throttle body what I was wondering is if I'm understanding the process correctly (tighten until no slack then back off full turn that gives about 1mm slack)

Has anyone done this
 

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Twin - I believe that the shaft of the adjuster is a standard M6x1.0 thread pitch, so yes, after tight then loosening one turn moves it 1.0 mm. I do it a little more crudely - I wiggle the throttle handle until it has just a hair of slack, then watch the cable to assure that there is slack.

JayJay
 

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I do it only slightly differently...

I pull the throttle cable body at the Throttle Body end. If it is not tight, I do the rest.

At 30k miles all the pieces-parts are still very happy with each other.... no tight, no slack, no wear, etc.

JVB is of course correct but he is also making a video for general use. My overall theory is don't "mess" with things till needed. I have seen guys get into a situation when they start messing with things... things that don't need messing with and stuff begins to happen.
 

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hopz said:
I do it only slightly differently...

I pull the throttle cable body at the Throttle Body end. If it is not tight, I do the rest.

At 30k miles all the pieces-parts are still very happy with each other.... no tight, no slack, no wear, etc.

JVB is of course correct but he is also making a video for general use. My overall theory is don't "mess" with things till needed. I have seen guys get into a situation when they start messing with things... things that don't need messing with and stuff begins to happen.
OR - if it's not broke don't fix it.
 

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Ponch said:
Entropy happens...
I was going to agree with you but got tired and forgot...
 

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Discussion Starter · #14 ·
If I check the slack by twisting the grip and turning the handle bars would that be sufficient to verify slack? If idle slack is different left side to right side will that matter as far as proceeding to do tbs?
Thanks
 

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Ponch... I forgot what CRS means... I think I used to know...

Twincruise... Turning the handlebars will probably not yield any information at all. Just for fun, next time you start your bike, turn the handlebars from one side to the other... notice any change of idle speed? I hope not.

When you do your next Throttle Body Synch... look and feel both sides where the throttle cable goes into the TB. You should have "some" slack. the book wants 1mm, but as we have suggested already, do not get too fussy about it. All you really need is "some" slack to ensure that the throttle cable housing is not interfering with settings.

A different slack from one side to the other is not a concern as long as the amount of air/fuel mix is equal on each side at just off of the closed position or at greater RPM.

(Note: the more open the TBs are the less noticeable a difference is noticeable- so do your TBS just off idle,)

What you want is balance between the throttle bodies... forget the cable slack unless it is causing interference.

OK kids... discussion question for the day... How does the Throttle Cable leave the handlebar in one cable and end up with two cables at the throttle bodies? Discuss quietly among your neighbors....
 

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hopz said:
OK kids... discussion question for the day... How does the Throttle Cable leave the handlebar in one cable and end up with two cables at the throttle bodies? Discuss quietly among your neighbors....
C'mon, Hopz, this one is too easy. The throttle cable actually leaves the handlebar as two cables, one pull, one push. They go underneath the fuel tank where they pick up energy from all those dead dinosaurs and end up in a dark box. Once in the dark box, they do what two energetic opposites tend to do in dark places and make two baby cables that go to the throttle bodies. The same thing happens with dust bunnies underneath your desk when you turn the lights out, and with paper clips when you close the drawer.

JayJay
 

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JayJay said:
C'mon, Hopz, this one is too easy.
Of course you know the answer, I was hoping some of the newer guys would have a BFO... you know a blinding flash of the obvious... how does one become two...?
 

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The slack (or lack of) in the cables at the throttle body will have no effect on the revs by turning the handle bars (unless he throttle cables are tight) they are actually different cables that come from the distributor box. The handle bar cables go to the box where they activate 2 shorter cables and then go to each throttle body. When your bike is at idle the stepper motors control the throttle bodies so as mentioned earlier the cable adjustment needs to be set off idle. I think 3 to 4k is best to set it at since this is the speed you will normally be running at anyway
 
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