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Idle speed

Discussion in 'Motorcycle Tech Talk' started by John Zuidervaart, May 4, 2006.

  1. John Zuidervaart

    John Zuidervaart New Member

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    Modesto California
    I have just purchased a new Heritage Classic with EFI. I installed a Screaming Eagle air cleaner, Vance and Hines 2into1 Pro pipe, and a power commander. Itseems to me that the idle is high I have adjusted out the idle screw on the throttle body and tried retarting the timing in the Power Commander but it still seems to idle alot faster than my 98 1200 sportster I have any ideas?
  2. Killer-B

    Killer-B New Member

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    John, first and foremost. I would rather have my cycle idle high than low, sure it sounds cool idling low, but, oil does not flow well at low RPM’s. I have never had EFI, always a carb for me. So, all I can say is did you get it remapped? Is there in intake leak? Is there a bad sensor? Are you SURE your turning the idle screw? Start there and let us know what’s going on. I am certain someone with EFI knowledge will chime in soon…
    Good luck.
  3. AFNurse

    AFNurse Moderator Staff Member

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    If your idle speed is between 1000-1100 (give or take) I THINK that is about where you should be with EFI. Cold engine will run a bit higher until warm. If you try going lower then 900 or 1000, I have been told that you may acheive the potato sound, but move little or no oil and therefore burn up your engine in short order. LOTS of folks here can give you even more details with MUCH more experteise!!.......guys......guys??!! ;)
  4. Killer-B

    Killer-B New Member

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    Also,,, what IS low RPM's? Do you have a Tach? Where is it idling? 1000 RPM'S..

    K-B
  5. chucktx

    chucktx Moderator Staff Member

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    there is no real idle control on efi.....it is controlled by the puter. as stated, it needs to idle high for oil flow to critical engine parts......get a tach and see what it is idleing at. guessing could cost you big time. all specs are in your service manual......i know ya got one of those...right?:D :D
    have fun and be safe
    chuck
  6. cowboy

    cowboy Moderator Staff Member

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    My 03 EG fathead does the same thing , i called a few different Dealers & they all say the same thing around 1k idle (my tackis in 100's ) so at 10 it's right on the mark & keeps the oil where it's should be :)
  7. John Zuidervaart

    John Zuidervaart New Member

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    Thanks Guys I just had it in for the 1000 mile service and they said that the higher idle is a characteristic of an EFI they checked it for me and it is running at 1000 rpm idle speed. I have another question though? They goose neck of the frame has some grease coming out of the bottom the dealer told it should be this way, it is messyand I have cleaned it out of the bottom a couple of time but after a couple of rides it is back and blows onto the valve cover. My Sportster doesn't do this either.
  8. CD

    CD Guest

    A little grease goes a long way....

    The idle speed of an EFI bike is supposed to be at 1000-1100 RPM for a couple of reasons. First, the EFI consumes more power so the RPM needs to be high enough to provide enough current to charge at idle. Second, the oiling system on a TC88 is unlike any other design H-D has ever made. Previous designs used high volume low pressure systems that relied on providing maximum flow across the bearings and bushings for lubrication. The TC88 relies on a more traditional high pressure and lower volume system. At low RPM, pressure is reduced and the bearings may not get sufficient oil and the piston cooling jets may not be firing (spraying) as designed. Considering the well known oil pump problems and the chain tensioner wear problems, I would want the most pressure and flow I can get.

    The Potato (or as old Dan would say, Potatoe) - Potato sound is just not going to be there on an EFI bike and, for that matter not the same on a TC88 or an EVO with electronic ignition.
    Why? Because the Shovel used points and mechanical advance. Even the V-Fire-I used a mechanical advance.

    Simply put, the mechanical advance varies the timing and at idle this can generate a "lope" which causes RPM changes which varies timing...The low idle, changing timing and the exhaust makes that sound.

    A lot of old school types converted EVO's to points if the electronic boxes failed and were able to get closer to that sound a Shovel or a Pan can make.

    Another reason EFI bikes just are not able to do the Tater-Tater dance is the fuel delivery system. The EFI bikes get steady pulses of fuel through the injectors making the engine run smoother. The carbed bikes rely on manifold signal (changes in vacuum) to pull the fuel charge into the engines. As the RPM varies so does the fuel charge and that adds to that lope.

    That grease is a good thing. Shows that someone actually greased the neck during the construction of your bike. The excess will go away soon enough. In the mean time, a little brake cleaner sprayed on a rag will help remove it. Note sprayed on the rag....brake cleaner can do nasty things to paint.
  9. CD

    CD Guest

    Whoa there Hoss! :eek:

    First, set that screw back to where it was or have the dealer adjust it. Second, put the map back to where it was.

    The Delphi EFI used electronic idle control unlike the Magnetto Marelli EFI. Playing with EFI settings is not a good thing unless A, You have the service manual and B, Some basic knowledge of how the EFI system works.

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