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carb issues on 80 gs1000g

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    carb issues on 80 gs1000g

    i just got a new (to me) 1980 gs1000g. it had been sitting neglected for sometime and needed some attention. I put everything back into order and cleaned the carbs and reinstalled them. The stock intake manifolds and ok, but i will need to replace them soon- does anyone know where i can get some in seattle? Anyways I got the bike started and it idles/starts up no problem, BUT when I rev the motor up to 5,000 rpm it bogs down and will not exceed this engine speed. When watching the slides in the carbs - as i rev it to this 5,000 rpm limit, only 3 of the 4 move upwards. I was wondering if anyone had an idea of what might still be clogged or any insight into. Everything inside the carbs looked to be in good shape when i cleaned/dipped them, I suppose one cleaning just may have not been enough and they need another.?
    Anyhow, thanks for any input and great site by the way...Will

    #2
    Sounds like dirty carbs or weak ignition to me.
    If you push up on the slides do they return quickly and all the same?
    1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
    1985 GS1150ES stock with 85 Red E bodywork.

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      #3
      when i push the slides up the all return at the same pace- not real quickly, but evenly. I did notice that the white wire that connects to the rectifier seemed to be getting quite warm during warm up. Not sure if thats related or not. When observing the spark produced at the plugs - it seemed very bright and looked good. All I can think is that the carbs remain dirty,I cleaned then #2 & #1 had some very nasty, sticky, dark, oily substance in the bottom carb bowls. #3 #4 looked like someone had already cleaned them...

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        #4
        lubricate the slides and see if that helps? WD 40 works, but don't get it on the rubber seal

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          #5
          I've seen that exact problem happen because of a bad igniter.
          1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
          1985 GS1150ES stock with 85 Red E bodywork.

          Comment


            #6
            If you are looking for the carb nipples that fit the cylinder head I have a set. I was getting an airleak and ordered a new set. After I got them they weren't much better than the ones I had which were almos in as good. Turned out all I needed was new O rings which I now have a supply of. If interested let me now at BSudderth@juno.com.

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              #7
              Just guessing, but if you can see the slides moving, I bet the airbox isn't installed.

              Without an airbox, you'll get exactly the behavior you're reporting. The bike won't rev and will generally run like poop.

              Seal up the airbox sides and air filter carrier with weatherstripping, clean and very lightly oil the filter element, install the airbox, and report back...
              1983 GS850G, Cosmos Blue.
              2005 KLR685, Aztec Pink - Turd II.3, the ReReReTurdening
              2015 Yamaha FJ-09, Magma Red Power Corrupts...
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              Please provide details. The GSR Hive Mind is nearly omniscient, but not yet clairvoyant.

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                #8
                Originally posted by bwringer View Post
                Just guessing, but if you can see the slides moving, I bet the airbox isn't installed.

                Without an airbox, you'll get exactly the behavior you're reporting. The bike won't rev and will generally run like poop.

                Seal up the airbox sides and air filter carrier with weatherstripping, clean and very lightly oil the filter element, install the airbox, and report back...
                What he said

                Your carbs need more vacuum to pull the slides all the way up. They're very sensitive to that.
                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


                  #9
                  Hi,

                  Yep, with the stock jetting, your bike needs a tightly sealed airbox installed. Here's what I did to my airbox sidecovers:



                  Do the same, as Mr. bwringer suggested, to the top of the air filter cage. You might even need new airbox boots, carb intake boots and O-rings. Check this out...

                  Air Intake Repair
                  Airbox removal, intake boots and O-ring replacement

                  It's a PDF file I just put together documenting the whole procedure. You can also have a look at Mr. roostabunny's airbox fix-up...

                  Airbox Sealing

                  (by Mr. Roostabunny)

                  ...and Mr. bwringer's information on O-ring replacement...

                  Replace intake boot o-rings

                  Then have another look at the required maintenance lists in your "mega-welcome", just to refresh your memory. Keep us informed. We'll help you keep your classic GS on the road and running properly.


                  Thank you for your indulgence,

                  BassCliff

                  Comment


                    #10
                    Originally posted by BassCliff View Post
                    Hi,

                    Yep, with the stock jetting, your bike needs a tightly sealed airbox installed. Here's what I did to my airbox sidecovers:



                    Do the same, as Mr. bwringer suggested, to the top of the air filter cage. You might even need new airbox boots, carb intake boots and O-rings. Check this out...

                    Air Intake Repair
                    Airbox removal, intake boots and O-ring replacement

                    It's a PDF file I just put together documenting the whole procedure. You can also have a look at Mr. roostabunny's airbox fix-up...

                    Airbox Sealing

                    (by Mr. Roostabunny)

                    ...and Mr. bwringer's information on O-ring replacement...

                    Replace intake boot o-rings

                    Then have another look at the required maintenance lists in your "mega-welcome", just to refresh your memory. Keep us informed. We'll help you keep your classic GS on the road and running properly.


                    Thank you for your indulgence,

                    BassCliff
                    This info is EXACTLY what i needed - all of BassCliff's stuff is superb, thanks for producing it all. I thought I'd post this just to get it back into the topical section, as so many people seem to have these airbox sealing troubles. The photo is a big help (to me anyway).

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