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Hi

My 2010RT had slack in the throttle from new such that there was a bit of twistgrip rotation before it comes off idle. I have taken out this slack using the cable adjuster so that the revs pick up without any free play. This feels better as there is now no slop and it still idles at the same speed.

However I wonder if the slack is there for good reason and having no slack will upset something.

If I have done a bad thing how much slack should I have ?

Kev
 

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There may have been too much slack for you. There is a specific spec on the proper amount of slack. It is about .5mm if I remember. You have to have some so the throttle bodies close completely in all conditions, bars turned, a very hot day etc. This slack is one of the tune up items to dial in. But it has to be such that each throttle body opens exactly at the same time and is just about the same opening at mid level RPM (3000 balanced air flow via vacuum meters). So now that you have messed with it look for some data on throttle sync for the new 1200 and it will confirm this. The other part of the sync is the idle stepper motor. Use to be done manually but now your bike does it each time you let the bike go through its start up sequence. So, in short it is an important part of the engine performance. (don't take all the slack out)
 

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I think your on to something. Take the slack out and it's more efficient. You know there's slack in the valve train and the brakes too. Sorry, I'm just a smart ass and couldn't resist.
 

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My 08 RT was "in spec" but too much slop as delivered. I dialed out almost all of it- no meaurements- just careful checking. It helps - the bike has a bit of inherent jerkiness when coming off idle especially before breakin is complete due to the usual extreme lean fuel programming. That could be dealt with with one of the resistance spoofers but I haven't fond that necessary on a broken in bike. The motors are tight and run a lot better after 6-10K miles and the off idle response seems smoother.
 

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I take away as much slack as I can, otherwise I have an on-off behavior at low RPM's.
One thing to pay attention to is that when the handlebar is turned fully to the right, the
engine may already rev if no slack at all was left with the handlebar straight.
Gaby
 

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Just for fun I got out the repair DVD and found that the factory slack at the throttle is 2 to 3mm. I agree this is excessive and I too reduce it. But there are good reasons not to eliminate it or go too small. The slack will change with heat. The famous driveline snatch is pesky. I just grab the clutch & use the brake not the engine when slowing down below a certain speed (very slow depending on what is going on) and do not do the on off throttle thing. Only on. This makes a big difference.
 
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