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Thread: Can't get idle slow enough.

  1. #1
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    Question Can't get idle slow enough.

    I'm doing a throttle body sync. on my 2000 r1100rt and am having trouble getting the idle to get down below 1250 unless I turn the brass screw(s) all the way in. It seems to balance ok using the twin max with the idle around 1250 and is fairly smooth running but would like the idle lower. I did the valve adjustments prior to moving to the throttle body sync, but am frustrated on the idle issue. Any idea's on what I am leaving out or doing wrong?

  2. #2
    Registered User roger 04 rt's Avatar
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    Quote Originally Posted by paneyes View Post
    I'm doing a throttle body sync. on my 2000 r1100rt and am having trouble getting the idle to get down below 1250 unless I turn the brass screw(s) all the way in. It seems to balance ok using the twin max with the idle around 1250 and is fairly smooth running but would like the idle lower. I did the valve adjustments prior to moving to the throttle body sync, but am frustrated on the idle issue. Any idea's on what I am leaving out or doing wrong?
    Do you have any add-on equipment or anything non standard?

    Which coding plug is installed?

    I ask because it seems either your throttles aren't fully closed, are they both hitting the throttle stops?

    Or The other possibility is that your mixture is too rich. Maybe no coding plug, Techlusion, etc.

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    Roger I have no added equipment. I do not know what the coded plug is (i'll have to look into that). I have been hesitant to mess with the throttle stops because of all the warnings, but have come close to trying.

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    Registered User roger 04 rt's Avatar
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    Under the seat, there is a relay and fuse box. Look at the center row, on the left is a yellow Plug that looks like a relay. It is a wiring jumper plug. For your R1100RT the factory plug was yellow. Check and see it is there. (Note there is an opening to the left of the yellow plug. Also ignore the red arrow.)



    Let us know if you have a plug in that location and what color it is. This plug tells your ECU what the engine and catalytic configuration is.

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    What did the bike idle at before you did any work?

    Mark

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    It is easy to tighten your throttle cables too much. That will result in your throttle screws being held off the stops. You can see it visually. You can also check by opening and closing the throttle. You should hear a distinct "snap!" on each side as the screw hits the stop. If you don't hear it your screws are not on the stops when the throttle is at idle. The butterflies are being held open by the cables, which raises your idle. The butterflies easily overcome the amount of "throw" the brass screws provide.

    If your cables are too tight you need to loosen the throttle cables and resynch with a tiny bit of slack.

  7. #7
    Registered User ANDYVH's Avatar
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    Yup, the first step is to set the throttle cable "slack", done at the LH throttle body where the throttle cable attaches tot the TB Cam plate. Once that is done, you match the RH TB to the LH TB for balance. Try to not adjust both TBs unless you are quite familiar with the TB setup procedure (as I found out).

    But in your case, since you have already adjusted the BBS (big brass screw), here is where I'd start. If you recall where the screws were (from seated) when you started this, set them back to that position. However, you also likely need to remove the BBS and clean them, and the ports into which they screw in. I use WD40 or something similar for this. Then turn them in till seated, and back them out to the start position. If you don't recall that setting, then turn them out 1.5 turns each.

    Now, hopefully you have not adjusted the idle stop screw (the one with the paint dab seal on it) on each TB. If you haven't, good, leave them alone. Then confirm the throttle slack, and adjust the RH TB to match the LH TB, first with the cable, and then fine tune the balance using the BBS. Then with the idle set, lock the throttle at about 2500 rpm and check the balance. Any adjustment above idle is done with the cables.

    If you have adjusted the idle stop screws, then you'll need to do the full Zero-Zero setup listed by Bob Lentini to reset the TBs for flow close to what the facotry had them set at. It is possible to do at home, even with cheapo mercury sticks, but it takes some diligence and patience. I have done it with good success on my 94 RS.
    Woodenshoe to Cheesehead

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    Thanks for replies and information. I will try and recap what I have done and what I can see/hear. There are no add-on equipment, the bike is stock. I did check for the coding plug and I do have the yellow plug in the correct spot. the throttle cables do have the correct amount of slack as far as I can tell and adjust for. I can hear and see the stop screw hitting the stop and I have not messed with the stop screws at all. When I started my tune-up the idle was at 1250 to 1300 by my tach. I did check the bbs before starting and it was 1 turn out (both left & right). I have been trying the procedure from ADV rider hall of wisdom "throttle body adjustment for dummies". Any ideas? Steve

  9. #9
    Registered User m_stock10506's Avatar
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    Would you include your location in your signature or your profile so others who might be located near you could offer their help.

    Have you checked for air leaks in the air tubes and their connections to the TBs?
    Michael Stock, Trinity, NC
    R1100RT, R100, R60/6

  10. #10
    Unregistered user norton's Avatar
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    You are probably not doing anything wrong... As the throttle bodies age there is a better chance for air leaks. I'm betting that you have a slightly worn shaft that is allowing air into the butterfly and increasing the RPM's, and the two sides are a bit uneven as far as the Big Brass Screw is concerned. Please make sure that you remove the BBS and clean it well with a cleaner that is good to go with fuel injection. Squirt some in the hole too. It wont really hurt anything if it idles a little high, so save your pesos for a rebuild if a through cleaning doesn't do it.

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    Have been working on the bike most of the day, doing the ride and adjust as per "throttle body adjustment for dummies". Here is what I have found. I think my throttle cable on the left throttle body did not have enough play. I say this because after readjusting this I could get the idle to come down. However it is not consistent, it seems to change for no reason. I did find that the right throttle body seems to have a worn shaft. It makes quite a racket and I can actually see it move/vibrate a noticeable amount. After riding/adjusting for a couple of hours I have been able to get a good balance between the bodies on throttle but when I go to compression the needle on my twin max goes all the way to the left (this is all while riding down the road). It seems to run fairly well but has a little more vibration than I would like. I have taken all your suggestions as a good reminder to check and recheck after moving one item as it does seem to effect another area. I have about 75000 miles on the bike and will probably need to rebuild the throttle body soon. Thanks for all the help. I live in western Oregon (North Plains) and if anybody that lives in this area and likes to tinker with their bikes I would like to meet up. Thanks again Steve

  12. #12
    Bluenoser
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    Don't forget that the choke cable affects the throttle plates as well. They all go into the boden box ( not sure of the spelling ), so you have to make sure that the choke cable is adjusted with the proper slack. When you put the choke on it should just move the throttle plate ever so slightly. Make sure that the choke cable isn't set so that it is holding up the throttle plate. You have to set the proper slack on all the cables including the choke & throttle at the handlebar before you do a sync. Give each of them their 1 or 2mm as recommended.

    The rattling on the right side throttle body is a common thing and I know that my 2000 R1100R did that, but it never affected getting the idle or syncing the carbs. If you can get down to 1100 I'd call it a day.

    It seems that if you get too fussy trying to get it to idle at 1000 then drive ability issues show up further in the rpm range. Its frustrating but make sure the bike is fully warmed up to its operating temp when you are doing a sync. If you do suspect an air leak, pass an unlit propane bottle around all the throttle bodies and intake area ( use one of the small ones you'd use for soldering plumbing ). If you have a leak the idle will speed up.
    1971 R50/5 SWB with R75/6 drivetrain
    2013 DL650

  13. #13
    Registered User twinsig's Avatar
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    my tb shafts were shot and i chased the sync like a rabbit on meth. it's sucking air and will only get worse. see Dan Cata on ADV forum.
    it's an interesting job, along with zero-zero sync. Worth the effort for the education & experience.
    Democracy is two wolves and a lamb voting on what to have for lunch
    Liberty is a well-armed lamb contesting the vote

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