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1990 FXR won't idle

Discussion in 'Motorcycle Tech Talk' started by Rumrunner, Dec 6, 2015.

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  1. Rumrunner

    Rumrunner Member

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    Thank You, the only port on the top of the carb goes to the VOES, then under that is the choke connection. There is a port on the bottom of the float tank that is not connected to anything. I have looked at other bikes this is an overflow. Thank you again.
    Rumrunner, Dec 10, 2015
    #21
  3. hotroadking

    hotroadking Super Moderator Staff Member

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    Yes don't cover that overflow,

    You should have a port that had stock a vac line that went to the fuel petcock
    all stock HD petcocks are vac operated, without it, no flow.

    Is your petcock on normal or reserve, it's possible that there is some more gunk
    in the tank that is blocking normal fuel demand enough that opening the choke or throttle allows more fuel.

    But that's what it appears, either air/vac leak or fuel delivery problem.

    Hard to tell on the net but FWIW...

    [​IMG]

    link for bigger image

    http://xlforum.net/photopost/watermark.php?file=51047
    hotroadking, Dec 10, 2015
    #22
  4. Lucifer

    Lucifer Well-Known Member

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    1990 didn't have a vacuum operated petcock...Gravity fed then...
    Probably wouldn't be a bad idea to replace fuel line and crossover line,the inside of the fuel lines can deteriorate sitting with gas in them especially if sitting a few years ... Did you check for good fuel flow from the tank to the carb,I'm not a fan of those inline fuel filters,they can be full of fuel but not flow well and plug up easily. Fuel strainer on petcock in the tank is all you really need.
    Like HRK said,you either have a bad air leak or low fuel flow. Did you change pilot jet or make sure none of the orifices are plugged,same with emulsion tube.
    Lucifer, Dec 10, 2015
    #23
  5. Rumrunner

    Rumrunner Member

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    I getting the upgraded rebuild kit from CV performance, also got that bucket/strainer carb soaking setup. Going to replace everything possible, completely disassemble it and let it soak overnight. With the info you guys have turned me onto, plus everything I've read I'm pretty sure its not getting fuel when I release the choke. I'll post the results.

    Sent from my XT1080 using Tapatalk
    Rumrunner, Dec 11, 2015
    #24
  6. hotroadking

    hotroadking Super Moderator Staff Member

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    I would get a set of intake manifold gaskets and replace them
    at the same time, you are already in there and they are not expensive
    to replace.
    hotroadking, Dec 11, 2015
    #25
  7. Rumrunner

    Rumrunner Member

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    Yup that was in the plans

    Sent from my XT1080 using Tapatalk
    Rumrunner, Dec 11, 2015
    #26
    Lucifer likes this.
  8. kenfuzed

    kenfuzed Administrator Staff Member

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    You mentioned that the bike sat for a while and that it only idles with the choke (enrichener) pulled out. The described condition to me is typical of a clogged idle passage. There are passages in the carb that connect the pilot jet, mixture screw port, and air intake port found at the front of the carburetor.

    Check out this carb trouble shooting page, item #3 which describes this condition.
    http://www.cv-performance.com/harley-cv-carburetor-tuning-issues/
    You need to clean out these passages since old lacquered fuel will easily clog there and effect the idle.
    [​IMG]
    kenfuzed, Dec 12, 2015
    #27
    kickstand68 likes this.
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