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jetting sizes for airbox and exhaust

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    jetting sizes for airbox and exhaust

    gonna be running a mac megaphone 4-1 exhaust with the stock airbox. anyone know the jetting size needed for peak performance on that setup? if you have links please send them. will i need different ones if i put in competition baffles and will they really increase the power much after jetted again.

    in florida in the US so noise isnt a complaint if competition are loud
    Ian

    1982 GS650GLZ
    1982 XS650

    #2
    You might want to bump the main a size and shim the needle. To shim the needle check the carb rebuild tutorial linked on bass cliff's website and in my signature. If power feels a little flat on top you can move one more main size.
    Ed

    To measure is to know.

    Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

    Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

    Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

    KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

    Comment


      #3
      Yep, what he said. Also, while you're in there, many old GS's were pretty cold natured, up one size on the pilots would usually make them a little easier to start & less time till you could push the choke off, with zero neg. effects. Just my opinion.
      1983 GS1100E, 1983 CB1100F, 1991 GSX1100G, 1996 Kaw. ZL600 Eliminator, 1999 Bandit 1200S, 2005 Bandit 1200S, 2000 Kaw. ZRX 1100

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        #4
        on the topic of chokes, the plastic switch for my choke broke so i dont have a choke setup for it (not like its up anyways), would giving it a small amount of throttle for 5-10 seconds a few times work the same way as a choke, or does it work differently, im talking small as in just bring the idles up to about 1400 from its 1100.

        if not where can i get an oem or same fitting piece online, its the plastic circle piece with the lever to turn the choke
        Ian

        1982 GS650GLZ
        1982 XS650

        Comment


          #5
          Originally posted by Nessism View Post
          You might want to bump the main a size and shim the needle. To shim the needle check the carb rebuild tutorial linked on bass cliff's website and in my signature. If power feels a little flat on top you can move one more main size.
          are you talking about street or competition baffles, sorry i was asking for both of them
          Ian

          1982 GS650GLZ
          1982 XS650

          Comment


            #6
            Timebom, Baffles will make very little or no difference in jetting. & NO, no throttle while starting, it shouldn't work. Just grab the end of the little choke rack rod & pull it out while cranking, (I know, hard to do while holding clutch lever in) does the same thing as choke. Yrs ago Kaw. had a little knob on theirs, to pull straight out it worked better, with less trouble than the cables ever did.
            1983 GS1100E, 1983 CB1100F, 1991 GSX1100G, 1996 Kaw. ZL600 Eliminator, 1999 Bandit 1200S, 2005 Bandit 1200S, 2000 Kaw. ZRX 1100

            Comment


              #7
              so stock airbox and mac megaphone 4-1 with street baffles. 1 main size up and 1 pilot size up? looking for the best sizes for the carb clean just trying to reassure. whats is the best setup in your guys opinion. will there be a difference rejetting it or is it not big enough of one that you could leave the jets stock.
              Ian

              1982 GS650GLZ
              1982 XS650

              Comment


                #8
                Originally posted by timebombprod View Post
                on the topic of chokes, the plastic switch for my choke broke so i dont have a choke setup for it (not like its up anyways), would giving it a small amount of throttle for 5-10 seconds a few times work the same way as a choke, or does it work differently, im talking small as in just bring the idles up to about 1400 from its 1100.

                if not where can i get an oem or same fitting piece online, its the plastic circle piece with the lever to turn the choke
                You can order a new cable from Parts Outlaw. They are not far from you, in Deland. Might be able to order it then pick up there to save some time. If you don't mind waiting another couple of days for them to ship it to you after they get it from the warehouse, shipping is only $4.99.

                When using the 'choke', do NOT open the throttle at all. The 'choke' circuit (actually an "enrichment" circuit) requires the high vacuum of a closed throttle to operate. If you open the throttle at all, you destroy that high vacuum and it will be hard to start.

                Comment


                  #9
                  what should i do to the jetting if i run the mac exhaust with a competition baffle, 2 main and 1 pilot?
                  Ian

                  1982 GS650GLZ
                  1982 XS650

                  Comment

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