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'79 GS1000 carb "emission" mixture screw setting

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    '79 GS1000 carb "emission" mixture screw setting

    So I messed up a bit when I took the carbs apart on the '79 GS1000 that I just drug home. I'm used to working on older "pre-emission" bikes. Bikes that don't have finnicky settings and have shop manuals that provide the number of turns out that the carb adjustment screws need to be turned for a good baseline setting.
    So anyway, I didn't count the number of turns out on the two mixture screws on each carb when I took them apart. There's the pilot screw on the bottom of each carb, and the air screw on the side. The manual simply states "Do not adjust these. If they've been tampered with, take them to a Suzuki dealer". I find that to be extremely frustrating.
    Does anyone know the number of turns out for these two screws for a good baseline? Thanks a lot.

    #2
    The air screw should be about twice the turns of the fuel screw. The fuel screw is on the bottom. Set it at 7/8 to 1 turn out from LIGHTLY SEATED and the air screw at 2 to get started. Then do highest idle on the air screws.

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      #3
      Greetings and Salutations!!

      Hi Mr. TheRadBaron,

      Let me dump a TON of information on you and share some GS lovin'.

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      Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. Now let me roll out the welcome mat for you...



      Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

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      BassCliff

      Comment


        #4
        Originally posted by TheRadBaron View Post
        So I messed up a bit when I took the carbs apart on the '79 GS1000 that I just drug home. I'm used to working on older "pre-emission" bikes. Bikes that don't have finnicky settings and have shop manuals that provide the number of turns out that the carb adjustment screws need to be turned for a good baseline setting.
        So anyway, I didn't count the number of turns out on the two mixture screws on each carb when I took them apart. There's the pilot screw on the bottom of each carb, and the air screw on the side. The manual simply states "Do not adjust these. If they've been tampered with, take them to a Suzuki dealer". I find that to be extremely frustrating.
        Does anyone know the number of turns out for these two screws for a good baseline? Thanks a lot.


        Any mods? Pods? Pipe? Jetting? If not then what mistercinders said

        Comment


          #5
          Thanks for the welcome and the responses. That's all some really good information. I'm a pretty experienced classic Japanese motorcycle mechanic, and I'm pretty good at tuning carbs. This is the first GS that I've put a wrench to, though. I know that every specific bike or series of bikes has its own set of quirks and it seems like this site is a wealth of information. I checked out the bikecliff website and it's a great site as well.
          Thanks a lot for the correct baseline on the carb screws. This bike does have some intake and exhaust mods. The stock airbox is gone and the exhaust is a 4-into-1 Vance and Hines with no baffle. The bike was this way when I got it. I plan to put a new muffler on it.
          I'm not usually a fan of individual pod filters, though I really like the easy access to the carbs afforded by ditching the stock airbox. I have a Yamaha FJ1100 with dual-carb Uni filters on it. They're oval with two carb spigots, so each filter goes on two carbs. These seem to work really well. Does anyone know if these are available for a GS1000?
          And one final thing; Does anyone know how I should adjust the carb screws for a baseline to account for the intake and exhaust mods? I know that I'll need to fine tune them, but the closer that I can start out, the better. Thanks very much.

          Comment


            #6
            You won't tune her in on just the screws. You'll need new main jets plus you'll have to lift the needles. Do a search on here and you'll find loads of carb solutions for your modded bike.
            79 GS1000S
            79 GS1000S (another one)
            80 GSX750
            80 GS550
            80 CB650 cafe racer
            75 PC50 - the one with OHV and pedals...
            75 TS100 - being ridden (suicidally) by my father

            Comment


              #7
              I'll try searching around for some info. My painfully slow rural internet makes it tough, though.
              I know that it will need tuning above and beyond the air and fuel screws and I'm prepared to do all that. It's just that this is the first bike that I've worked on that has a separate air and fuel screw for the pilot circuit. The intake and exhaust mods will certainly be cause for an adjustment on the pilot screws and it would be nice if I could start out with a know good adjustment for a GS1000 with similar mods and fine tune it from there.
              I apologize if this has been covered a bunch before. My slow internet makes it terrible to search through these threads for the right info. Living in the countryside is the only way to live for me. I have about as much privacy as is possible and I'm free from citizen and government intrusion. The slow internet is quite a downside, though. I'd much rather be wrenching on my new GS than waiting for another thread to boot up. Thanks.

              Comment


                #8
                Ball park figures to experiment around:

                Fuel screws (the ones underneath) 3/4 of a turn out.

                Air screws (the ones on the side) 1 1/2 turns out

                Pilot jets. 15s (standard) may work and you can tune in via the screws. But possibly 17.5s - no bigger.

                Needles. Raise the needle (lower the clip) to #4. You might need to go to position 4 1/2 by using a washer.

                Mains. I would start at 125-130 and see what colour you get on the plugs.
                79 GS1000S
                79 GS1000S (another one)
                80 GSX750
                80 GS550
                80 CB650 cafe racer
                75 PC50 - the one with OHV and pedals...
                75 TS100 - being ridden (suicidally) by my father

                Comment

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