Yet another carb jetting question

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Anonymous

    #1

    Yet another carb jetting question

    Like everyone else that has ever modified airfilters and exhaust I'm having trouble. I have a 82 GS 1100 with 4 to 1 exhaust system and pod filters. I have installed the K and N stage 3 kit as stated in their instructions. My test ride showed that I had gained an amazing amount of low end power. On the top end I have nothing. When the bike reaches 5000 rpm it bogs and has no more power. I believe that this is a problem with the main jet. Should I size up or down?
  • earlfor
    Forum LongTimer
    Charter Member
    GSResource Superstar
    Past Site Supporter
    • May 2002
    • 42413
    • off grid cabin 1/24/26 7pm

    #2
    Re: Yet another carb jetting question

    If at 5000 rpm letting off the throttle slightly produces an increase in power, then youre too rich. Usually bogging is a sign of too rich and going flat/hollow is too lean.

    Earl


    Originally posted by Rockford
    Like everyone else that has ever modified airfilters and exhaust I'm having trouble. I have a 82 GS 1100 with 4 to 1 exhaust system and pod filters. I have installed the K and N stage 3 kit as stated in their instructions. My test ride showed that I had gained an amazing amount of low end power. On the top end I have nothing. When the bike reaches 5000 rpm it bogs and has no more power. I believe that this is a problem with the main jet. Should I size up or down?
    Komorebi-The light filtering through the trees.

    I would rather sit on a pumpkin and have it all to myself than be crowded on a velvet cushion. H.D.T.

    Comment

    • Anonymous

      #3
      What do you mean by flat or hollow?

      Comment

      • KEITH KRAUSE
        Forum Guru
        Charter Member
        GSResource Superstar
        Past Site Supporter
        • Oct 2002
        • 8862
        • Angeles Forest, So.Calif./Red rocks of Southern Utah.

        #4
        Re: Yet another carb jetting question

        Originally posted by Rockford
        Like everyone else that has ever modified airfilters and exhaust I'm having trouble. I have a 82 GS 1100 with 4 to 1 exhaust system and pod filters. I have installed the K and N stage 3 kit as stated in their instructions. My test ride showed that I had gained an amazing amount of low end power. On the top end I have nothing. When the bike reaches 5000 rpm it bogs and has no more power. I believe that this is a problem with the main jet. Should I size up or down?
        At what throttle position are you when it bogs? A steady 5000 rpm in top gear, you are on the jet-needle. Don't take the Dynojet "base settings" too seriously, they usually turn out to be just a starting point. Did you remove the 2 floatbowl vent tubes? Have you read your plugs yet?
        And on the seventh day,after resting from all that he had done,God went for a ride on his GS!
        Upon seeing that it was good, he went out again on his ZX14! But just a little bit faster!

        Comment

        • Anonymous

          #5
          At what throttle position are you when it bogs? A steady 5000 rpm in top gear, you are on the jet-needle. Don't take the Dynojet "base settings" too seriously, they usually turn out to be just a starting point. Did you remove the 2 floatbowl vent tubes? Have you read your plugs
          When I hit 5000 rpm at full throttle the bike tops out. What float bowl vent tubes am I supposed to remove? I read my plugs and they are reading a good mixture. Thanks for having patience with a GS newbie.

          Comment

          • KEITH KRAUSE
            Forum Guru
            Charter Member
            GSResource Superstar
            Past Site Supporter
            • Oct 2002
            • 8862
            • Angeles Forest, So.Calif./Red rocks of Southern Utah.

            #6
            Besides the fuel line and vacuum line, do you have 2 tubes that just go under the seat or ? Not to be confused with the 4 floatbowl overflow tubes.
            With some jet kits, Dynojet requires that these be removed.
            Bogging at full throttle usually means too rich. This is usually the main, but the bogging can be influenced by the needle being set too rich also. The "overlap", especially during roll-ons, of the two jetting circuits, can be difficult to jet.
            What size mains did you get in your kit? What size is in it right now? What is the jet needle's clip position (from the top)? Were the carbs cleaned inside? How about everything else, float heights, diaphragms/o-rings, carb synch', throttle valves? Spacers on the needle/clip replaced correctly?
            For the motor to be apparently running that rich, you should not be getting good plug reads. Maybe your reads are mostly showing how the pilot and needle circuits are overlapping. Such as 60 mph and below speeds.
            Sounds like you need to try a smaller main, if your kit allows. You may have to lower the needle height also.
            And on the seventh day,after resting from all that he had done,God went for a ride on his GS!
            Upon seeing that it was good, he went out again on his ZX14! But just a little bit faster!

            Comment

            • earlfor
              Forum LongTimer
              Charter Member
              GSResource Superstar
              Past Site Supporter
              • May 2002
              • 42413
              • off grid cabin 1/24/26 7pm

              #7
              If too rich, the engine blubbers and the exhaust note stays deep, too lean and it sounds flat or hollow. The same way it sounds if you run out of gas.
              The exhaust sounds weak and the tone is not as strong. A decreasing echo in a hollow tube. :-)

              Earl


              Originally posted by Rockford
              What do you mean by flat or hollow?
              Komorebi-The light filtering through the trees.

              I would rather sit on a pumpkin and have it all to myself than be crowded on a velvet cushion. H.D.T.

              Comment

              • Anonymous

                #8
                Earl,
                I'm getting the hollow sound like when you run out of gas.
                Kieth,
                The needles are set 3 spaces from the top. The carbs haven't been synced. I can't remember the jet size exactly it was something like 175. Where do the float vents connect to the carbs?

                Comment

                • KEITH KRAUSE
                  Forum Guru
                  Charter Member
                  GSResource Superstar
                  Past Site Supporter
                  • Oct 2002
                  • 8862
                  • Angeles Forest, So.Calif./Red rocks of Southern Utah.

                  #9
                  Originally posted by Rockford
                  Earl,
                  I'm getting the hollow sound like when you run out of gas.
                  Kieth,
                  The needles are set 3 spaces from the top. The carbs haven't been synced. I can't remember the jet size exactly it was something like 175. Where do the float vents connect to the carbs?
                  I'm not sure where your 2 vent tubes connect. If similar to my carbs, they are on #2 and #4 carbs, right above the floatbowls. They probably use a 3/16'' nipple and tube. Are yours still on? Did'nt Dynojet give you at least 2 sizes of mains? If so, do you have the larger ones in right now? Do you have the instruction sheet for your kit? What are their suggested base settings? How about answers to my other questions posted earlier?
                  And on the seventh day,after resting from all that he had done,God went for a ride on his GS!
                  Upon seeing that it was good, he went out again on his ZX14! But just a little bit faster!

                  Comment

                  • KEITH KRAUSE
                    Forum Guru
                    Charter Member
                    GSResource Superstar
                    Past Site Supporter
                    • Oct 2002
                    • 8862
                    • Angeles Forest, So.Calif./Red rocks of Southern Utah.

                    #10
                    Rockford, if you look in this same section, there is another topic "'82 1100E
                    looking for jetting recommendations". One of the members replying said they have a 4-1 pipe and pod's and a Dynojet kit. They say they have it jetted well. Maybe you can get help there. Let us know if you still have questions.
                    And on the seventh day,after resting from all that he had done,God went for a ride on his GS!
                    Upon seeing that it was good, he went out again on his ZX14! But just a little bit faster!

                    Comment

                    • Anonymous

                      #11
                      Kieth ,
                      I'll check out the other thread. Maybe that will help.

                      Comment

                      Working...