NEW 89 sportster carb issues.

Discussion in 'Sportster Models' started by pike1612, May 23, 2010.

  1. pike1612

    pike1612 Member

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    "Dead Spot" up to 1/4 throttle."misses""stumbles" upon acceleration up to 1/4 throttle.Will not maintain 1/4 throttle upon acceleration or at highway speeds at 1/4 throttle.Once past 1/4 throttle it runs like it was shot with nitrous..I have-Replaced vacuum piston,cleaned and inspected the pilot jet,main jet,needle,float needle and seat,accelerator pump diaphragm,adjusted float level to 18.5mm,tested the floats for bouyancy,checked for intake manifold leak,checked the piston slide for smooth travel,removed and cleaned the fuel tank,and replaced the o ring in the float bowl.What am i OVERLOOKING?
     
  2. glider

    glider Veteran Member

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    What size low speed jet are you using?
     
  3. pike1612

    pike1612 Member

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    Im am using the stock jet 42
     
  4. glider

    glider Veteran Member

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    Try upping it to a 45 or 46 jet.
     
  5. pike1612

    pike1612 Member

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    will do brother-i will keep ya posted.
     
  6. glider

    glider Veteran Member

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    Good deal.:D
     
  7. pike1612

    pike1612 Member

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    I changed it today to a 45" ..much better but still a dead spot between 45-50 mph. i may adjust the float level a tad to try to compensate or just order a 46' jet.im ALMOST there bro :)
     
  8. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    You may be able to smooth out the flat spot by raising the the slide needle by placing a couple of washers under it
    that will raise the area of the taper that is being used in comparison to slide height so gives a wee bit more from the main jet through all throttle positions

    Brian