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  • Jetting question

    I have a 2004 Roadstar with stock carb. I have after market exhausts with baffles.(Vance & Hines short shots)
    The intake is a K&N cone shape filter ,no oil. Stock jetting.
    It was running and starting fine. Then I changed the stock air filter for the K&N and it has been hard to start or would not start
    because the battery started to get run down.
    Do I need to change the idle jet? Some say yes and some say no. Any comments?

    Thanks!

  • #2
    First thing to do is charge the battery. If you are running after market filter and exhaust stock jetting will be lean. So charge battery then give a couple twist of the throttle to see if it starts by fuel from the accelerator pump. also are you pulling the choke out when it is hard to start?

    Comment


    • Lucky
      Lucky commented
      Editing a comment
      It starts with the choke out. After the battery was charged.

      Still coughing and occasional spitting or back firing.
      I played around with the PMS screw and idle and got it to start acting normal.
      I will check it in the morning on a cold start.

  • #3
    Originally posted by Lucky View Post
    I have a 2004 Roadstar with stock carb. I have after market exhausts with baffles.(Vance & Hines short shots)
    The intake is a K&N cone shape filter ,no oil. Stock jetting.
    It was running and starting fine. Then I changed the stock air filter for the K&N and it has been hard to start or would not start
    because the battery started to get run down.
    Do I need to change the idle jet? Some say yes and some say no. Any comments?

    Thanks!
    Does it start by pulling the choke all the way out ?
    Also, if you can remove it and say cover half to 3/4 the are of the carb opening does it start ?
    My guess is that your old filter might had been dirty thus not flowing much - sounds like the new K&N is flowing more air.

    If you have after market pipes+K&N most likely you will need to rejet.
    OPR

    Comment


    • Lucky
      Lucky commented
      Editing a comment
      The aftermarket pipes have metal baffles with fiberglass wrapping.

  • #4
    May I ask why you run your knn filter dry? You could probly save a bunch of money by using a paper filter that will filter better that a dry knn.

    Comment


    • Lucky
      Lucky commented
      Editing a comment
      The stock filter and housing is too large and does not allow adjustments.

    • Lucky
      Lucky commented
      Editing a comment
      I kind of don't like oil on a filter. Then you open a can of worms.
      Like what kind of oil ? K&N oil etc.,.

    • daveto
      daveto commented
      Editing a comment
      Thanks, I can see where you are coming from from my 2 stroke days. And truthfully if a velocity stack with no filter can be used then it’s probly not a huge deal. I was just curious.

  • #5
    I have changed the idle jet to a 37.5 It was a 35 which was stock.

    I appreciate all comments and advice.

    Comment


    • Father Pobasturd
      Father Pobasturd commented
      Editing a comment
      Did that change solve the problem? I know when I went to that filter it seemed like the bike would spit or cough easier than it did previously with the stock filter I attributed this to a less restrictive filter allowing the motor to suck more air than it needed to when opening the throttle quickly. As long as I just roll it open a little slower I don't have the problem. But if what you did cured that I may have to look into it. Also, I would like to see a new pic since you changer the breather. I bet it makes the motor look even bigger.

  • #6
    Click image for larger version  Name:	image_12401.jpg Views:	3 Size:	69.9 KB ID:	84961 Yes- the larger idle jet did help the problem.

    The photo is a little dark. I will have to retake the photo.

    Comment


    • highvoltage
      highvoltage commented
      Editing a comment
      Wow...... What a great looking bike and fantastic job.

  • #7
    Today I started the bike and used about 50% choke for about a minute then it would idle on its own.
    Bike was cold and outside air temp was about 80 degrees in the garage.

    I had to play with the idle and PMS screw to get it to run right.
    I know the PMS screw is not 3 turns out but not sure of its exact number of turns out.

    Comment


    • #8
      A #40 pilot would work better for you with a 1700. If you are gonna keep the stock needle I would also add a shim under the clip. You can use the shim that is above the clip that the little spring sits on. It really isn't needed there above the clip.

      Comment


      • Lucky
        Lucky commented
        Editing a comment
        I removed the needle and there was a washer already under the nylon spacer.
        Should I add another washer? Thanks.

      • Lucky
        Lucky commented
        Editing a comment
        I ordered the #40 idle jet today. Thanks daveJ.

      • davej
        davej commented
        Editing a comment
        yes add a 2nd under the clip.

    • #9
      Thanks daveJ . I went back and added that second washer .

      Comment


      • #10
        Let us know how the test ride goes when you install the #40

        Comment


        • Lucky
          Lucky commented
          Editing a comment
          Will do. I should get the jet in the next day or two.

      • #11
        After adding the 37.5 idle jet and a washer under the needle, the next day it just would not start.
        So after several attempts with a fully charged battery I thought something must be wrong. Not sure what.
        I removed the carb and could find no problems.

        I removed the 2nd washer under the needle and the bike started right up!

        So I am waiting for that #40 idle jet and will test that as soon as it arrives.

        So right now it is a stock 2004 carb set up with the exception of the 37.5 idle jet and K & N cone shaped filter with no oil on it.

        Comment


        • Spydr
          Spydr commented
          Editing a comment
          What do you mean, no oil on it? Straight out of the box, with no additional oil? Or was it cleaned but not oiled?

        • davej
          davej commented
          Editing a comment
          That is odd that a 2nd washer would keep it from starting. it only puts you at 1/2 step richer on the needle that comes in play mostly at cruising speeds. That shouldn't have much if anything to do with starting.

        • fastjohnny
          fastjohnny commented
          Editing a comment
          davej you're absolutely right about the main jet and needle not having a thing to do with starting. Starting is the enricher circuit and idle circuit

      • #12
        Spider, it was a new K &N filter out of the box. Good question.

        Comment


        • Spydr
          Spydr commented
          Editing a comment
          Kinda what I figgered. But someone was confused about that earlier.

        • roadiemort
          roadiemort commented
          Editing a comment
          New out of the box is oiled the right amount.

      • #13
        I did not know that RoadieMort.

        Comment


        • Spydr
          Spydr commented
          Editing a comment
          You never wondered why it was red?

        • roadiemort
          roadiemort commented
          Editing a comment
          Almost all K&N air filters come pre-oiled and ready to use. The filter oil we use is red. A new oiled filter will appear red-pink in color. Some crankcase vent air filters come unoiled, however, they come with a small packet of K&N filter oil so they can be oiled before use.

      • #14
        You mean the color of the filter?

        Comment


        • Spydr
          Spydr commented
          Editing a comment
          I give up

        • roadiemort
          roadiemort commented
          Editing a comment
          My K&N RC 1980 filter media was pink out of the box. It does not have a red element like some of the car ones.

      • #15
        I received the #40 idle jet today (Sept. 9th 2019). It was delayed in the mail.

        I will install it tomorrow and see if it is better than the 37.5 idle jet.
        It was running right with the PMS screw at 4-1/8 turns out with the 37.5 idle jet.
        aftermarket exhaust with metal baffles wrapped in fiberglass and K&N filter, dry.

        # 40 jet installed. I will report back soon.

        Comment


        • #16
          OK...2004 Roadstar 1700 with Vance & Hines short shots with Vance & Hines metal baffles with packing.
          K & N cone filter, no oil. #40 idle jet ,stock needle stock setting, stock main jet.
          PMS open close to 2-3/4 to 3 turns.
          83 F degrees Tucson altitude 2,389 ft.
          Starts when cold with some choke, choke off after about 2 minutes.
          Idles and throttles without hesitation.

          Thanks to DaveJ. for recommendations.

          Comment


          • #17
            I need recommendation for a jet kit so I can get the adjustable needle. Thanks.

            Comment


            • #18
              Get the Barons. also check your messages for my return reply

              Comment


              • Lucky
                Lucky commented
                Editing a comment
                Thanks Davej

              • Lucky
                Lucky commented
                Editing a comment
                For some reason I am not getting any messeges in my messages box.
                I am going through the Tech articles carb section.

              • davej
                davej commented
                Editing a comment
                I got your message as a visitor message and just replied to it .

            • #19
              It turns out that I have a 2003 Roadstar carb but I thought I had a 2004 Roadstar Carb. So I ordered stock jets for the 2004 carb way back when I started building my custom rigid frame Roadstar.
              That is why the main jet is a 182.5! I am sure when I get the Barons carb kit I will be changing the main jet to a different size.
              The air jet in the opening of the carb is the same (#100) everything else is the same too.
              Just the jets and needle needed changing.

              Comment


              • #20
                the 1600 and 1700 carb are essentially the same other than the main jet size. The difference between them other than that is meaningless as far as fitting and working on either bike when jetted properly.

                Comment


                • Lucky
                  Lucky commented
                  Editing a comment
                  Thanks for confirming that Davej. I did not want to have to buy another carb.
                  I am kind of wondering what main jet size Barons is going to give me.

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