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    78 gs1000 carb question

    I have a 78 gs1000 with a stock motor and exhaust. I am going to be rebuilding the carbs and I am going to change the stock air filter to pods. The question I have is do I need to put a dynojet stage one kit in them or will the be okay.

    Thanks for the help Krank
    Last edited by Guest; 02-19-2011, 12:05 AM. Reason: update

    #2
    You will have to rejet.
    Ed

    To measure is to know.

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    Comment


      #3
      Originally posted by kranker1450 View Post
      The question I have is do I need to put a dyna stage one kit in them or will they be okay.

      Krank
      To answer your question... YES.
      Is an upgrade to the ignition a good idea? ... Always.

      Daniel

      Comment


        #4
        VM carbs don't really need a kit, since all the necessary parts are available

        Why the pods with a stock exhaust?
        1978 GS 1000 (since new)
        1979 GS 1000 (The Fridge, superbike replica project)
        1978 GS 1000 (parts)
        1981 GS 850 (anyone want a project?)
        1981 GPZ 550 (backroad screamer)
        1970 450 Mk IIID (THUMP!)
        2007 DRz 400S
        1999 ATK 490ES
        1994 DR 350SES

        Comment


          #5
          Thanks for the help guys.

          Where would be a good starting point for jetting?

          Big T, I just dont have the extra cash right now for the exhaust also. And I really don't like the stock filters. Since I had the carbs apart to clean them I figured it would be a good time to put the kits in..

          Is Z1 the best place to get the dynojet kit.

          7981GS, I will be upgraded the ignition on it also as soon as the funds allow it. What system would you recommend for it. I would like to have something that has a rev limiter in it as it will be ran down the 1/4 mile.

          Thanks Krank
          Last edited by Guest; 02-19-2011, 12:17 AM. Reason: more info

          Comment


            #6
            If I can make a suggestion it would be to wait until you can buy a quality pipe to better match the increased flow of the new pods. Also, if the pods are not K&N that can complicate the jetting. It may seem convenient right now to change just the pods but keep in mind a stage 1 kit isn't designed for pods only (correct me if I'm wrong) and a stage 3 kit is for BOTH pods/pipe. The stock pipe and pods are a poor flow match. Jetting issues are almost built-in. The restrictive pipe will eliminate much of the gains of the pods.
            I can help you with jetting if you install a pipe and a stage 3 kit or if you choose to use separate jets because you can't afford or find a DJ stage 3 kit. The kit gives better results though and more often than going with separate jetting parts.
            If you insist on re-jetting just for pods then I'll suggest a main jet increase of 4 to 5 full sizes (20 to 25). Your stock mains are 95. So I think a minimum of 115 is needed and a maximum of 120. I'd probably try 117.5 and be right in the middle. This suggestion is largely based on DJ's stage 3 kit that supplies a main jet equivalent to a 130 Mikuni main. DJ and Mikuni size their jets differently but the supplied 138 DJ main is approx' the same as a 130 Mikuni. So you have an increase of 7 full sizes (7 X 5) to go from a 95 to a 130. That's for both quality pipe and K&N pods. So I'd say 4 to 5 of those sizes increase would work for just pods though you have to keep in mind the advice above is based on using K&N pods. As always, test to see what works. Test the mains at full throttle.
            Then you'll need to richen the jet needle positions. That's the most work on your carbs and you need proper fitting tools and basic knowledge to do it right. Also, to re-jet correctly, you need to bench synch the carbs slides and then follow that with a vacuum tool synch. Whenever you disturb the VM slides you must re-synch. Getting the jet needles right the first time is difficult and because you're using parts that are a poor flow match you may have more trouble. I'd allow one full richer position for the pods only. That means raising the needles by placing the e-clip one position lower on the jet needles (position 4). I doubt you would be rich but you could still be lean and have to make further adjustments. You have to test to see. For the jet needle, ride at a solid 1/2 throttle position, chop off, and note performance/check the plugs.
            As for the pilot circuit, you MAY be able to simply richen the circuit by turning the pilot fuel screws (underneath/engine side) OUT a little. Maybe 1/4 additional turn to start. Test at minimal throttle openings (cruise around town) and note performance/check the plugs. Do what the plugs/performance say. If necessary, you may need to increase the pilot jets to 17.5.
            Lastly, I suggest you remove the two floatbowl vent lines and leave the ports open to breath. This is suggested in the DJ jetting instructions. If you leave them on it can compromise bowl venting and the result is fuel starvation at various levels depending on crosswinds, etc.
            I'd wait but that's up to you. Also, no matter what you decide, I'd replace the manifold o-rings while you have things apart. They're inexpensive but if the manifolds still have the stock Phillips screws they can be difficult to remove. Use an impact driver and a GOOD fitting bit. Then replace them with Allen bolts. Coat the new o-rings with some hi-temp bearig grease to help them last and torque to about 9 ft/lb is plenty. More torque just flattens the o-rings and they tend to crack sooner.
            Last edited by KEITH KRAUSE; 02-21-2011, 02:21 PM.
            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


              #7
              I agree, wait until you get the pipe before you go thru rejetting

              Buying a stock air filter in the meantime is cheaper than having sets of jets you won't use again

              Again, you carbs don't need a DJ kit. Bumping up your main jet and raising the needle generally does the trick
              1978 GS 1000 (since new)
              1979 GS 1000 (The Fridge, superbike replica project)
              1978 GS 1000 (parts)
              1981 GS 850 (anyone want a project?)
              1981 GPZ 550 (backroad screamer)
              1970 450 Mk IIID (THUMP!)
              2007 DRz 400S
              1999 ATK 490ES
              1994 DR 350SES

              Comment


                #8
                what kind of pipe upgrade is required for the stage 3 jets with pods?

                Comment


                  #9
                  Originally posted by traviseckley View Post
                  what kind of pipe upgrade is required for the stage 3 jets with pods?
                  Something that flows much better than stock. V&H, Yosh, Kerker...
                  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


                    #10
                    Thanks Keith for the great info!!!! I was going to go with a pipe and new pods but the cash fell through. I will hold on to the dj kit until I have the other parts and take your advice on just re jetting and needle adjustment. Where would be a good place to get the jets?

                    Thanks krank

                    Comment


                      #11
                      Never mind found them! Thanks again..

                      krank

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