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Might be a fueling issue. RPM question.

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    Might be a fueling issue. RPM question.

    So being used to a bike that will hit 17k rpm in about .9 seconds with a smile on it's face, I'm wondering what the RPM range should be on the GS. This is in neutral, kickstand down; I wish it was rideable already.

    Anyhow I can get it to redline, but that's WFO and it seems to not like going from 7500-9k and absolutely will not go above 9k. And no, I wasn't just sitting in my driveway holding it at redline, but I did want to see how high up it went, or if it totally loses it's ass at high rpms.

    1750-7500 is smooth as butter though. Can't wait to test it under load to see that all go to hell in a handbasket, lol

    On a somewhat related note, when I wrapped it to 9k and chopped the throttle, it dropped to 1200, sputtered, and died. Fuel starve?

    105 mains, stock exhaust, pods. 1 7/8 turns on air screw, 1 turn on fuel screw, no choke.

    #2
    So, what do your plugs look like?

    That motor should pull smoothly past redline
    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


      #3
      Hi,

      Yes, my first thoughts are fuel starvation and perhaps the valve clearance.


      Thank you for your indulgence,

      BassCliff

      Comment


        #4
        Hm... Sounds like I need to locate a set of 107.5 mains. I put 110s in and it bogged out and died under load. Valves are good, haven't checked the plugs yet, but when I pulled them prior to trying the 110s they were a nice light brown except #2 which was nice and oily from the blowby I had.

        I noticed a lean condition (maybe) on my #1 cylinder, it was running a good 60* hotter than the other 3 and had what looked like a miniscule smoke **** from the head gasket.

        Comment


          #5
          How can you do plug chops if the bike is not rideable?

          You have to get it on the road and hold specific throttle settings to get proper readings on the plugs.

          RPM range? Mine all idle smoothly at about 1100 and will go readily to redline. I tend to keep the revs lower than most, most of my running is under 5000. Be aware that there are TWO power ranges with this bike, though. It is a mild commuter bike with respectable power below 6000 RPM, but take it above that, you will think that somebody switched the cams on you. There is a noticeable surge in power up to redline. Probably not nearly as much as you are used to, but it will scoot along just fine.

          .
          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


            #6
            Originally posted by Steve View Post
            How can you do plug chops if the bike is not rideable?

            You have to get it on the road and hold specific throttle settings to get proper readings on the plugs.

            RPM range? Mine all idle smoothly at about 1100 and will go readily to redline. I tend to keep the revs lower than most, most of my running is under 5000. Be aware that there are TWO power ranges with this bike, though. It is a mild commuter bike with respectable power below 6000 RPM, but take it above that, you will think that somebody switched the cams on you. There is a noticeable surge in power up to redline. Probably not nearly as much as you are used to, but it will scoot along just fine.

            .
            Track terminology. Chopping the throttle means to take it from WFO to closed. Typically used in reference to an epic high side.

            "That noob chopped the throttle when his rear end stepped out, and yardsaled his whole f****n kit"

            Carbs clearly need a fair amount of work. No big deal, just keeping busy until I can afford parts to make it roadworthy.

            Comment


              #7
              While I would not call it track terminology (I have been chopping the throttle since I started riding/driving in the 60s) Steve confused it with plug chops, which is reading the plugs after a specific type of run, used in tuning the carbs.
              Since you already know how to read plugs, it should not be an issue once the bike is rideable enough to fine tune the carbs.
              Since it clearly has fueling issues, I have to ask: Have you done the CV carb cleaning/replacing o-rings work yet? If not, that should be your first step. Including fuel bowl gaskets, it may set you back ~$30 plus shipping. Also check the o-rings at the head; they should be replaced if you have not already done so.
              Just some thoughts.

              Comment


                #8
                Get the bike running on the road and then judge. Reving the bike in neutral provided no meaningful information.
                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


                  #9
                  Originally posted by koolaid_kid View Post
                  Steve confused it with plug chops, which is reading the plugs after a specific type of run, used in tuning the carbs.
                  No, I didn't really confuse it, I just wanted to make sure that he wasn't confusing "chopping the throttle" while sitting in the driveway with a proper plug chop to read the color on the plugs.

                  .
                  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


                    #10
                    To answer your first question it should rev from idle to way way past redline in about .6 seconds or so.
                    http://img.photobucket.com/albums/v5...tatesMap-1.jpg

                    Life is too short to ride an L.

                    Comment


                      #11
                      Thanks for the input.

                      Ness: I think the fact that it won't go above 9k provided a lot of useful information. Information that tells me I may have had some settings off when I put the 110s in.

                      Comment

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