How Do I Adjust Idle?

[grant1856]

I just got the bike. I put the carbs and airbox on it and it fired right up but the idle is way too high. My only other bike was a single cylinder that had one idle adjustment knob. Is there a way to adjust the idle on my XS? Do I have to adjust all 4 or is there a single one to adjust? I want to take it for a ride so bad but I am afraid I am going to pull a wheelie at the 3-4000 rpms it is running at.

Thanks.

Grant (the newbie)

[Dragon Tamer]

First, make sure your starting/richener/choke lever is pushed all the way in. If it is out to the middle or outer position your idle will be very high.
There is a single idle adjustment between the center two carbs above where the throttle cable hooks up, it looks a little like a crude gear. It can be adjusted with a long screwdriver with the gas tank installed but initially it is easier to raise the tank up to access the control.
Also you should have your carbs synchronised any time you have made any changes to the carbs or air filtration system, out of sync carbs will give you serious idle issues.

[fredintoon]

Hi Grant,
What year and model XS do you have?
Building this info into your sign-off line will help things along.
Like the tamer sez, first make sure the enrichener (fancy word for choke) lever is not pulled out.
Don't worry, at ~4,000 rpm idle it won't go into gear without such a crunch that you daren't do it anyway.
On my XS11SG there's a knurled screw under the cable arm that adjusts how far the carbs can close. Make sure there is enough slack in the throttle cable to let you adjust the carb closure until the bike won't run at all without the throttle being opened a little. Adjust the stop until it idles nice at ~ 900 rpm. Take up the excess slack in the throttle cable. There is also the issue that you now have 4 carbs rather than the single carb you are used to. The cable operates carb #3. Carbs #1, 2 & 4 are operated by carb #3. There's a spring loaded adjuster between each carb that allows them to be balanced. There's a "how to" in the tech tips that explains the procedure. Typically, after you balance the carbs the idle speed will have changed so mebbe it's best to balance the carbs first.

[grant1856]

No Progress Yet

I see the knob that you are referring to to adjust the idle of #3. I started it, adjusted the knob both ways and nothing changed. Which way should I adjust it to idle down? Counter-clock-wise? I will read up on te synchronization. I hope that is something I can do without specialty tools.

I included pics of the bike and the knob.

<http://i91.photobucket.com/albums/k3...6/DSC04000.jpg>

<http://i91.photobucket.com/albums/k3...6/DSC04001.jpg>

Thanks,

Grant

[Dragon Tamer]

You turn it counter clockwise to lower the idle speed, try it with the engine off and you should see the carb shafts turning slightly. If not check the cable and make sure that it is not bound or adjusted too tightly. Again, make sure that the "choke" lever is pushed IN toward the carbs all the way, pull it out and push it back in again. While doing that make sure that all four carb levers are moving.
If all of this is working you will have to sync the carbs before you can go further, if only one carb is out of sync it will prevent you from attaining a proper idle setting. Syncing does require special tools but you can make your own easily and cheaply. Use the search feature on this website, there are many good threads on how to do this.

[fredintoon]

Hi Grant,
is your idle adjustment screw photo from the top looking down like Clymer's book shows it or is the screw's knob underneath like mine is? No matter, they all work the same way. The carb rack is spring loaded to close itself and the cable pulls it open.
The idle adjuster screw's end acts as a movable stop to prevent the carbs being totally closed, it holds them open just a crack so the engine will idle. If you look under there (NOT with the engine running) and turn the twistgrip you can see how it all works. I suspect that your throttle cable is adjusted too short so that there is still a gap between the idle adjuster screw and it's stop. That is, the cable is holding the throttle partially open even when the grip is rolled completely closed. There should be an adjuster in the cable just under the twistgrip.