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Left carb leaking after new float needle valves installed

Discussion in 'XJ Technical Chat' started by Dave Franks, May 20, 2019.

  1. Dave Franks

    Dave Franks New Member

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    Hey guys I have a 82’ xj650 maxim. Has 6sigma jet kit installed and 4 into 1 exhaust with pod filters. I had my left and furthest right carbs leaking fuel. Removed the carbs everything was clean, just installed new carb float needles & now just the furthest left carb is leaking fuel, headers leaking fuel also. Bike starts up & takes off up to 4 grand before I hit the kill switch. Any ideas on what’s going on ? Thanks in advance
     
  2. Jetfixer

    Jetfixer Well-Known Member

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    Did you wet set your float level?, A hanging idle is usually a vacuum leak , what do you have the idle knob set to? 1200 rpm is about where it should be set.
     
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  3. Dave Franks

    Dave Franks New Member

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    How do you set the float level? I started backing the idle knob all the way out. Once all the way out it still took off @Jetfixer
     
    Last edited: May 20, 2019
  4. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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  5. Jetfixer

    Jetfixer Well-Known Member

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    Your synch may be off as well ,if you moved any of the synch screws this will cause one carbs to pull more than the others . Sorry dont have time to explain this , might tonight cheers.
     
  6. Jetfixer

    Jetfixer Well-Known Member

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    Okay there are 3 synch screws and the idle knob makes up for 4th , you have to have to have either a momonometer 2 bottle or a 4 vacuum gauge manifold, or my favorite the mercury pro motion . You need to check your intake manifolds if you have weather cracks a good smear of RTV will help, check all 4 plugs on nipples a leak there can be as simple as that. Another thing do you have the stock clamps on the intake boots... using hose clamps is not a good idea , too tight can actually crack the carb body. The stock clamps only tighten so far and that is it. Now here is what you can do for a bench synch ,pull carbs take 2 business cards cut in 2 ( in other words 4 pieces) put under all 4 carbs if you have no resistance pulling on card turn synch screw till you have resistance once you have all 4 carbs set up remove cards hold up to light you will see a smiley face held up to light only barely. Reinstall carbs and see how it runs .
     
  7. XJ550H

    XJ550H Well-Known Member Premium Member

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    check that your throttle and choke cable are not switched.

    and
     
  8. Dave Franks

    Dave Franks New Member

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    I have a motion pro mercury gauge. I’ll check for vacuum leaks and I have the stock clamps installed , thanks for the reply @Jetfixer I installed a 6sigma jet kit to the carbs & cleaned @k-moe
     
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  9. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Were the throttle shaft seals and idle mixture screw o-rings replaced?
     
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  10. Dave Franks

    Dave Franks New Member

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    No I didn’t change the seals on either @k-moe
    What’s the effect that those leaking would cause ? It’s expensive to get parts into Canada
     
    Last edited: May 22, 2019
  11. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Vacuum leak, resulting in a hanging or runaway idle.
    Why you should replace butterfly (throttle shaft) seals.

    Two #11 (SAE) Buna-N o-rings can be used to replace each seal, but it's not preferable IMO.
     
  12. Dave Franks

    Dave Franks New Member

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    Ahh your a smart man @k-moe im going to throw the carbs in tomorrow probably and vacuum test it , I’ll let you know how it goes. Thanks buddy for your help
     
  13. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Vacuum leaks at the throttle shaft seals can be difficult to diagnose., which is why I tend to reccomend replacing them if the carbs are off for cleaning. If the carb bodies were soaked with the seals in place they have to be replaced.
     
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