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Rough low end, Idle too

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    Rough low end, Idle too

    Hey guys thanks for bearing with me again. My '82 1000s Kat is almost done now.

    She idles at different rpms, going alittle high then for no reason going low and almost dying. Also, and I'm sure it's probably related, when I'm in first and take off she hesitates badly. I really have to feather the clutch and throttle, until I get to about 20 mph and then she takes off like a rocket. 2nd is the same way.

    Valves clearances good, new battery, clean tank and good petcock, new uni-filter pods (came on bike), fresh fuel, plugs good and gapped-all firing, good wires. Carbs have been chemical and heat cleaned by a shop w/no adjustments.

    Any thoughts? It could very well be the new pods, but I don't think these uni-filters would affect the carbs that much.

    Also, could it be a float not set right? I noticed one wasn't set the same as the others.


    #2
    Originally posted by Escobarclan View Post
    Carbs have been chemical and heat cleaned by a shop w/no adjustments.
    Personally, I think every shop should have an adjustment every now and then.

    Seriously, though, it sounds like a carb problem to me. If there have been no adjustments to the carbs, that could be your problem. You should have main jets a bit larger than stock (maybe 10 numbers or so), possibly raised the needles a bit and definitely tweaking the idle mixture screws. On top of all that, the carbs need to be synchronized. I don't know if your model uses o-rings in the intake tubes or not, but that is another common cause for erratic idle speeds. The hesitation you are experiencing is likely from a very lean carb mixture and lack of sync on the throttle settings.

    .
    sigpic
    mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
    hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
    #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
    #2 son: 1980 GS1000G
    Family Portrait
    Siblings and Spouses
    Mom's first ride
    Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
    (Click on my username in the upper-left corner for e-mail info.)

    Comment


      #3
      Originally posted by Steve View Post

      On top of all that, the carbs need to be synchronized. I don't know if your model uses o-rings in the intake tubes or not,

      .
      No O-rings on the 16V engines, but everything else applies. A good set and sync will likely take care of the problem. It does sound like a lean condition so larger idle circuit jets may be needed.

      Comment


        #4
        Assuming that's a header exhaust I see on the bike a full jet kit is in order unless the jets have been changed already. Of course, carb sync is needed also although the symptoms you describe are not likely related to sync other than the hunting idle.
        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


          #5
          Wow guys, I'm getting blown away by this. If I needed a new jet kit what would I look for? As far as adjusting the idle mix, is that inside the carb somewhere? All that is outside the carb is 1 'jet' screw that the book tells me not to mess with, that it's set at the factory and is only for sync'ing

          I've worked on alot of projects but this is my first bike, #4 exhaust is turning blue, #3 just alittle. Is this a lean problem? A problem at all? Should I be concerned that I may be burning a valve?

          I'm about to break down and send her to a shop, but this EATS ME UP having to resort to this.

          I think I'm getting bald spots again

          Comment


            #6
            If a full rejet is in order...then a Stage #3 kit (which will cover both the mains and pilots), seems to be the route that most take. Someone here will have a link. Good luck getting a shop to work on a bike that old, modded, and have to do a rejet.:? You don't want a shop working on it anyway...most of the techs working today, were not even born when these bikes were built. Do it yourself (with help from the GSR) and you'll know what you have and how to care for it.

            If you still have the air screw caps in place, I highly doubt that your bike has been rejetted. Those screws are needed to correct for even minor changes over time. Those caps can and must be removed, inorder to set the carbs correctly. It looks like you're in for the carb GURU award, by the time this project is back up and running right. We'll get it! :-D

            Comment


              #7


              Just wondering but why would one float height be different from the others? Your first post indicates the carbs were dipped thus I assume they also put them together afterwards? One would have to consider their work suspect based on the messed up float height.

              And yes, you adjust the pilot screws - they are set at the factory for emissions purposes but that was a LONG time ago. I seriously doubt this will make a huge difference though unless the carb passage is plugged up from sludge. If the screws are set to 2.5 turns from closed you are going to be very close to ideal.
              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


                #8
                Originally posted by Escobarclan View Post
                All that is outside the carb is 1 'jet' screw that the book tells me not to mess with, that it's set at the factory and is only for sync'ing
                The book tells you not to mess with it because Big Brother wanted the emissions to be as low as possible. That meant that the bikes ran like crap, even when new. Oh, and that screw has nothing to do with sync'ing the carbs, it's the three adjusters between the carbs that handle that chore.

                .
                sigpic
                mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
                hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
                #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
                #2 son: 1980 GS1000G
                Family Portrait
                Siblings and Spouses
                Mom's first ride
                Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
                (Click on my username in the upper-left corner for e-mail info.)

                Comment

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