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1980 GS 450L vacuum AND oil leak

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    1980 GS 450L vacuum AND oil leak

    Hi everyone,

    I'm new to the site (love it so far) and I've searched all the threads for answers to my questions but can't find them. I have a 1980 GS 450L (9000mi) which is in great shape except for 2 problems.

    First is an oil leak which I noticed when I first bought the bike about 2 months ago (at that time it was more like a weep), but foolishly ignored. Where the shift lever connects to the crankcase some oil had weeped out and dripped onto the part of the frame that runs underneath the left foot peg/ shifter assembly area. This morning when I started the bike I noticed some fresh oil dripping on the ground. It's most concentrated on the left side of the bottom side of the crankcase, with oil running along the cooling groves but only on the left (right side is clean). So, the question is now what? How do I find the source of the leak without taking the engine apart or is there no other way to find out? (a previous post suggested using flour, but I want the bike to get me to work, not bake a cake -- flower in the cylinders doesn't sound tasty).

    Second problem is that the bike idles high, anywhere between 2000-4000 rpms but only after its been running for a couple of minutes. Previous posts suggested that this is an air/vacuum leak. They recommended spraying carb cleaner around the carbs to find the leak. Won't this eat the rubber hoses and/or seals/gaskets? If this is not a good solution, how should I find the source of the leak?

    Finally, I'm having trouble finding an OEM manual for this bike. Any suggestions? I tried a few of the sites linked to other posts (manuals.com, etc.) but they're no where close. Should I settle for the Clymer?

    Thanks everyone,

    Noah

    #2
    Take off the sprocket cover and clean the area to remove oil - spray can engine cleaner works well. After the area drys, start the engine and look for the source of the leak. Common leak sources are the shift lever seal and/or the clutch pushrod seal. Both can be replaced by digging out the old seal and pushing in a new one. Easy fix. Hardest thing is getting the screws out of the sprocket cover - you will need an impact driver (the kind you hit with a hammer).

    Your high idle is a result of an air leak. Replace the carb boot runner O-rings and the boots themselves if they are hard and cracked. Don't bother messing around with spray to try to find the leak it doesn't always work. Just replace the o-rings and be done with it.
    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


      #3
      Your high idle is a result of an air leak. Replace the carb boot runner O-rings and the boots themselves if they are hard and cracked.


      I'm going to reveal my self as a complete newbie, but I've scoured the service manual and the internet and have no idea what the heck "the carb boot runner" is or where to find the accompanying o-rings. Is this inside the carb? Something to do with the airbox? I have no idea. Someone please throw me a bone.

      Thanks,

      noah

      Comment


        #4
        Parts #27 and #28 for your bike.



        Welcome to the GSR. :-D

        Oh...here ya go....fetch!

        Comment


          #5
          Originally posted by Dave8338 View Post
          Parts #27 and #28 for your bike.



          Welcome to the GSR. :-D

          Oh...here ya go....fetch!

          THat's cold Dave, really cold!!!

          Comment


            #6
            Hi!
            As for the manual I would recomend the Haynes for this bike - it covers just about anything you could possibly want to know.

            Your oil leak is probably one of two seals behind this cover.
            It is either the clutch pushrod seal, or the gear shift shaft seal(try saying that a few times in a row )
            Both seals can be exchanged without splitting the cases, but for the shifter seal you need to remove the right hand side engine cover to get to the other side of the gear shaft. Pulling this shaft out on the other side makes for a much easier operation when changing the seal.
            The seal itself can be pryed out on the left side using a screwdriver or open ended wrench. A new seal can be found in a decent hardware store, it is just a standard metric oil seal.

            The clutch pushrod seal is larger in diameter and I think you need a OEM seal. The original seal must be pryed out using some force (steel reinforced seal) but take care not to damage the mating surfaces. Replacement is a straight drop in.

            -blo

            Comment


              #7
              Originally posted by blo View Post
              Hi!
              As for the manual I would recomend the Haynes for this bike - it covers just about anything you could possibly want to know.

              Your oil leak is probably one of two seals behind this cover.
              It is either the clutch pushrod seal, or the gear shift shaft seal(try saying that a few times in a row )
              Both seals can be exchanged without splitting the cases, but for the shifter seal you need to remove the right hand side engine cover to get to the other side of the gear shaft. Pulling this shaft out on the other side makes for a much easier operation when changing the seal.
              The seal itself can be pryed out on the left side using a screwdriver or open ended wrench. A new seal can be found in a decent hardware store, it is just a standard metric oil seal.

              The clutch pushrod seal is larger in diameter and I think you need a OEM seal. The original seal must be pryed out using some force (steel reinforced seal) but take care not to damage the mating surfaces. Replacement is a straight drop in.

              -blo
              Could also be the gear position indicator switch seal. If that goes oil comes out :P Very nasty. I found that out the hard way when I went to change the switch lol.

              Comment


                #8
                Dear Professionals,

                Thanks for your help everyone, I truly appreciate it. Things are going very slowly. The carb boots are in fact cracked at the top, but I don't know if that was there before or is a result of the 10 rounds I went with the carbs before finally wrestling them off at 2:30am last night.

                Now I can't get the bottom screw out of the boot on the right side of the bike. There's no room to use an impact driver because the frame and airbox are in the way. The other three came out only very reluctantly and this last one is almost completely stripped. I've drenched it several times in PB Blaster, used a dead blow hammer on the bit of the impact driver, and just bent the head of a brand new offset flathead screwdriver trying to get this bastard out. The screw is now bending the head of my drivers, can you believe that??!! Granted the driver was made in China, but still, after all that and its bending screwdrivers!! So I don't know what to do now, before I keep trying the same routine and end up completely stripping the screw. Again, its the bottom right screw on the right carb boot of my 80 GS 450L.

                Thanks again everyone,

                N

                Comment


                  #9
                  Originally posted by fifthcolum View Post
                  Dear Professionals,

                  Thanks for your help everyone, I truly appreciate it. Things are going very slowly. The carb boots are in fact cracked at the top, but I don't know if that was there before or is a result of the 10 rounds I went with the carbs before finally wrestling them off at 2:30am last night.

                  Now I can't get the bottom screw out of the boot on the right side of the bike. There's no room to use an impact driver because the frame and airbox are in the way. The other three came out only very reluctantly and this last one is almost completely stripped. I've drenched it several times in PB Blaster, used a dead blow hammer on the bit of the impact driver, and just bent the head of a brand new offset flathead screwdriver trying to get this bastard out. The screw is now bending the head of my drivers, can you believe that??!! Granted the driver was made in China, but still, after all that and its bending screwdrivers!! So I don't know what to do now, before I keep trying the same routine and end up completely stripping the screw. Again, its the bottom right screw on the right carb boot of my 80 GS 450L.

                  Thanks again everyone,

                  N
                  Here is what you do. Get a piece of wood,1by 2 or whatever is handy. Then put it on the metal flange at the top of the boot where it connects to the engine and use a hammer and tap it the direction the screw is suppose to turn.You will actually be using the flange to loosen the screw.Believe me ,it works!! Then go to the hardware store and get some allen head screws to replace them.Then torque them to 6to 8 ft. lbs.

                  Comment

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