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    #1

    Throttle response?

    OK guys, what would be your thoughts if you took your 750 out for a top end road test and it topped out at 120 mph and after holding it there for about two miles, when you slowly started to roll off the throttle, it noticably started to increase top end speed? I'm thinking I'm still a "fuzz" lean on top end. The plugs are burning about perfect, so there isnt any discrepancy to read. :-)

    Earl
    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.
    Tags: None
    #2
    Just a thought?? maybe the throtle blades are going past center when wide open

    Comment

      #3
      Hi. I'm not sure what you mean by 'throttle blades',but if you mean the throttle stop screw may need to be turned in,I agree. If the slides are going too far up,the symptom would make sense. Good advice SqDancerLynn1. KK.
      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

        #4
        I beleive Earl's 79 GS750EN has VM carbs (mechanical linkage to the slides). The throttle butterflies are only on the later models with the BS (diaphram linkage to slides). It does sound like it may be a tad lean. It might be worth it to check the throttle linkage (right down at the carb level) to ensure there is no slop in the linkage between the individual carbs. If there is, full throttle may be pulling them slightly out of sync. The other thing that I am thinking about is that the slides may be over opening and causing eddying of the air flow (I beleive this is what Keith Krause is referring to). I'm not sure that this carb bank has a stop screw to prevent over-opening but it might be worth checking.

        Personally, If I could get my GS750 up to 120mph today I wouldn't be complaining about it. It was -35C here last night and at present is a baumy -19C. You folks living in the south really turn me green.

        Comment

          #5
          Good thought, but unfortunately, I have mechanical VM's and there are no throttle blades.

          Earl


          Originally posted by SqDancerLynn1
          Just a thought?? maybe the throtle blades are going past center when wide open
          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

            #6
            AH HAAAA!! Yes, there most certainly is a stop screw for limiting slide travel. I think youre correct that the slides raising too far would propogate a back swirl and screw things up. I feel, so, so, DUMB! :-) Why didnt I think of that. :-)

            I'm not complaining about 120 mph. :-) I guess I'm an anal retentive wrench with my bike. I just cant accept anything less than mechanically flawless. The old girl is presentable in the looks dept., but she wont win any prizes there. Mechanically though, she flows like a turbine. :-) :-)

            Earl

            Originally posted by Junkman Frankenbiker
            I'm not sure that this carb bank has a stop screw to prevent over-opening but it might be worth checking.

            Personally, If I could get my GS750 up to 120mph today I wouldn't be complaining about it. It was -35C here last night and at present is a baumy -19C. You folks living in the south really turn me green.
            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

              #7
              Dunno about the slides, but the symptom you describe is usually a text book case of slightly lean on the main jets. But if your bike will hit 120, I'd leave it alone. It's sure running better than most.

              Comment

                #8
                Had the same problem with my GS850, running a Laser 4-into-1 exhaust.
                After I fitted a stock exhaust, the problem was solved.
                Earl, did you change anything on the exhaust side lately?

                Comment

                  #9
                  NO JoJo, the exhaust system is the 4 into two that was on the bike when it was manufactured. :-) Stock airbox, and filter element.

                  Earl


                  Originally posted by jojo
                  Had the same problem with my GS850, running a Laser 4-into-1 exhaust.
                  After I fitted a stock exhaust, the problem was solved.
                  Earl, did you change anything on the exhaust side lately?
                  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

                    #10
                    Count yourself lucky you have some extra go at the top end if you need it!!!!

                    Comment

                      #11
                      Heh heh, I have noticed three or four times this past week, I should try to remember to go a little lighter on the throttle in turns as I have "chirped" the rear tire loose by being heavy handed. Blasted skinny metzelers just dont have enough grip. :-) :-)

                      Earl


                      Originally posted by saaz
                      Count yourself lucky you have some extra go at the top end if you need it!!!!
                      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

                        #12
                        Originally posted by earlfor
                        ....Blasted skinny metzelers just dont have enough grip. :-) :-)
                        Earl
                        That's what you get for using an old fogey's ME88 rear tire.

                        Comment

                          #13
                          Yeah Simon, I may have to break down and put sport tires on the ol girl.
                          I gotta quit tuning and tweaking though. Its reaching a point of not being far short of scary fast. :-) :-) :-) I wonder where I might be able to get footpeg rubbers by the gross? :-)

                          Earl

                          [quote="Simon Waters
                          That's what you get for using an old fogey's ME88 rear tire. [/quote]
                          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

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