Carb issues

Discussion in 'Sportster Models' started by poolguy, Jun 12, 2012.

  1. poolguy

    poolguy Member

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    Posted here before, thought I had it figured out, but...97 1200, straight pipes, rejetted with a 180 and 42 jets, drilled holes in back plate of stock air cleaner. Runs darn good going down the road but if I rap on it, it sputters, and after a 20 minute ride, I swear it smells hot? and when I get in my driveway, it backfires just as I ready to turn it off. Any advice?
     
  2. Jack Klarich

    Jack Klarich Expert Member

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    Still sounds lean try a 45
     
  3. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    The stock air box on your sportster is very restrictive and by drilling the holes in the back plate you are letting a lot of air through the system the 42 slow jet will not allow enough fuel through for the airflow at slow engine speeds so there will be some spluttering
    As the slow jet keeps delivering fuel at any engine speeds then you will be lean throughout the rev range
    As Jack said a 45 slow jet should make a fair bit of difference

    Brian
     
  4. Jeff Klarich

    Jeff Klarich Well-Known Member Contributor

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    I drilled out the air box on 1 of my metric bilkes and found what Brian said to be true. More air more gas, good advice by both.
     
  5. poolguy

    poolguy Member

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    plan to work on it this week when I can, will those "spacer/ washers" do anything for me?
     
  6. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

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    If you are referring to the washers under the needle. It probably would help with your acceleration and pull through the gears but as others have said you may try a .045 for your issue.
     
  7. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    The carb slide needle is tapered putting wasters under the needle seat raises it to be further on to the taper this is good for fine adjustment of the main jet as it will allow incremental steps
    For example if a 190 main jet is too much and a 185 not enough 2 washers should give the equivalent of somewhere in between
    But first the slow jetting needs to be correct as the slow jet fuel is delivered at all throttle openings

    Brian