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    sputtering/ no acceleration

    Hey all,
    1981 gs850gl. Valve clearences done, carbs cleaned, new carb O rings, new intake O rings on the head side. I do have pod air filters because the existing airbox was crap. Verified fuel to all 4 bowls, all plugs are a tan to sandy color (too lean?). When I put the carbs back together I only turned out the fuel screw 1 1/2 to 1 3/4. Could that be the problem? The bike has no problem starting and idles great. When I go to ride, it sputters and has no acceleration.
    Any suggestions?

    Thanks.

    #2
    Put the airbox back on, those pods are leaning the mixture. You can order new airbox to carb rubber boots and reseal the airbox with weatherstrip material available from hardware stores. The bike won't run properly with pods unless you rejet the carbs - huge can of worms and way more work than just refurbing your airbox.
    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

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      #3
      I agree with Nesssim, but

      You probably overoiled your pods and they're not flowing enogh air
      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

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        #4
        Nessism, thanks for the reply. I put the airbox back on and what a difference. Before I wasn't able to even ride without it sputtering. Now it is much better and it's at least rideable. But I am still getting a little hesitation at highway speeds. I am using the stock rubber boots, they seem to be in decent shape, no cracks or dry rot and I put new hose clamps around them, but do you think there is still air getting in? I am going to order new boots regardless. I put new plugs in also. I haven't synced the carbs yet, I'm ordering the tool, how many turns should I have the fuel jet out just to be able to ride until I get them synced? Could not having the carbs synced be causing the hesitation at the higher rpm's?
        I'm stoked that I can at least ride it, now I just have to get it dialed in.

        Thanks!

        Comment


          #5
          Set the pilot screw to 2.5 turns out, and then fine tune to achieve the highest idle setting. Out is rich, and the setting effects low speed driveability. Sync does not cause hesitation like you describe unless it is way off.

          One last tweak can help the lean stock carbs; shim the needles to raise them. The needle height is controled by the plastic spacer on top of the needle because the spring pushes up. Take off the spacer and replace with a couple of small washers about 1/2 the height of the stock plastic spacer. This will raise the needle and increase the richness of the mixture a little. Makes a noticable difference in my opinion.
          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


            #6
            Originally posted by mopar19 View Post
            Nessism, thanks for the reply. I put the airbox back on and what a difference. Before I wasn't able to even ride without it sputtering. Now it is much better and it's at least rideable. But I am still getting a little hesitation at highway speeds. I am using the stock rubber boots, they seem to be in decent shape, no cracks or dry rot and I put new hose clamps around them, but do you think there is still air getting in? I am going to order new boots regardless. I put new plugs in also. I haven't synced the carbs yet, I'm ordering the tool, how many turns should I have the fuel jet out just to be able to ride until I get them synced? Could not having the carbs synced be causing the hesitation at the higher rpm's?
            I'm stoked that I can at least ride it, now I just have to get it dialed in.

            Thanks!
            To answer your question, I would say yes - carbs out of synch can feel like a hesitation or lack of power when you turn the throttle. If 2 of the carbs open ahead of the other 2 it will cause the mixtures to be different between the carbs.

            Get them synched before you troubleshoot further.

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