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1980 GS850 Rebuild

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    1980 GS850 Rebuild

    Hello GS Forum. I got my hands on a non-running GS a couple of months ago CHEAP, so I'm slowly working my way through it in an effort to get it back on the road. It has a fair oil leak somewhere (I think toward the top end, TBD), and the wiring is pretty hacked up. I'm taking it slow and trying not to spend too much money in case it turns out to be a lost cause. Here's my progress so far:

    I removed the Vetter fairing. It won't be going back on. Also removed the tank (remarkably clean and rust free inside), seat, airbox and carbs so I could give the bike a thorough degreasing.

    Now that it's clean enough to touch, I started working through the wiring. The PO had installed a new generator, but he told me it still wasn't charging. I disconnected and cleaned all the wiring harness connectors, labeled everything and temporarily reconnected the hacked wires so I could do some testing on the electrical system and the engine.

    I temporarily connected one of my jet ski batteries and was able to confirm that the engine turns over. One small victory! So, I shot a little oil in each cylinder and checked compression. Compression in all four holes was good, so I think it's safe to start spending a little money on this thing.

    I disassembled the carbs, cleaned them up, adjusted floats and replaced o-rings. Carbs, like the gas tank were cleaner than I expected and in overall pretty good condition. I reinstalled the carbs and hooked up an auxiliary fuel tank, cleaned the plugs, topped off the oil and tried to start it. It took a little spinning, but eventually fired up!! It was loaded up initially because of the oil I'd put in the cylinders, but it eventually cleaned out and ran pretty good. I hadn't installed the air box, so it liked to stumble through mid range, but it would rev out and it idles well. It also shifts through all the gears like it should. I had identified some mistakes the PO had made wiring up the new generator, so it's now charging as well. Victory #2. Time to spend more money.

    My next step is to get it reassembled far enough to do some road testing and hopefully find out where the oil leak is. So, I purchased a new battery and have the rubber pipes between the air box and carburetors on order (~$85! Ouch, but the old ones were rock hard). I also bought a used headlight (couldn't mount the one from the Vetter) and cleaned up the brake systems. I ended up needing a rebuild kit for the front master cylinder, so that's on order. Finally, I reworked my temporary wire connections to a more permanent state. I tried to restart, but now I'm getting no spark at any of the plugs. I'm working my way back through my wiring, but haven't found the culprit yet. I did find that someone had installed an aftermarket signal generator at some point (bonus!?). I was hoping to post a picture so I could get help identifying the manufacturer, but the site will only let me attached on file. Maybe I'll follow up later.

    So, here's my first real question to the GS experts. In trouble shooting my no spark situation, I'm finding good voltage (bright light on my test light) at the orange/white wires to the coils with the ignition switch turned on. I'm getting a very dim light at the black and white coil wires with the ignition on. When I run the starter, the dim light kind of flickers. I guess I was expecting something a little more dramatic. Is this typical of a non-points ignition system? Is my signal generator not getting adequate voltage? The service manual only addressed points, so I'm not sure what to investigate next.

    Thanks in advance for your help. I'll continue to update, and I'll post more pictures when I have something worth showing off.

    2020-09-11 18.50.21.jpg
    1980 Suzuki GS850GT
    2011 Ducati Multistrada 1200
    1993 Honda XR650L

    #2
    Here's a picture of the signal generator. If anyone knows the manufacturer or can provide any other information, I'd appreciate it. Thanks.

    2020-10-20 17.44.41.jpg
    1980 Suzuki GS850GT
    2011 Ducati Multistrada 1200
    1993 Honda XR650L

    Comment


      #3
      One more shot of the bike before the initial disassembly. Sorry for posting out of order.

      00X0X_9MnfJwsvwfi_0t20lM_1200x900.jpg
      1980 Suzuki GS850GT
      2011 Ducati Multistrada 1200
      1993 Honda XR650L

      Comment


        #4
        Welcome to the forum! It’s usually the CDI that goes out (spark box) not the signal generator. The Dyna ignition fits that bike and is worthwhile for peace of mind in my book....

        How are the brakes? The Twinpot brakes fit that bike... at the very least you should flush all the calipers out and change the lines for new braided ones. Safety first....

        Cheers,

        Dan
        1980 GS1000G - Sold
        1978 GS1000E - Finished!
        1980 GS550E - Fixed & given to a friend
        1983 GS750ES Special - Sold
        2009 KLR 650 - Sold - gone to TX!
        1982 GS1100G - Rebuilt and finished. - Sold
        2009 TE610 - Dual Sporting around dreaming of Dakar.....

        www.parasiticsanalytics.com

        TWINPOT BRAKE UPGRADE LINKY: http://www.thegsresources.com/_forum...e-on-78-Skunk/

        Comment


          #5
          Although it is often mis-labeled as "CDI", you don't have an actual CDI on your bike.

          There is no large capacitor that gets discharged to provide the spark, hence no "Capacitor Discharge Ignition".

          What you DO have is a box of transistors that act like the mechanical points, Suzuki calls it the "Ignitor". You should always see a strong voltage (should be VERY close to battery voltage) on the orange/white wire. The wires at the other end of the coils are effectively switched ground wires, so they WILL flicker.

          Won't help your "no spark" situation, but have you checked your valve clearances? That is a MUST DO item for any bike where you don't know the history.

          .
          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
            Thanks for the input fellas. I'll continue to sort the wiring this weekend. I'm suspecting a bad ground, but who knows. My master cylinder rebuild kit showed up, so that's what I worked on yesterday. Good brakes all the way around now.

            Valve adjustment is definitely on the to-do list. I expect to have to replace some gaskets (maybe even the base gasket) before this is all over with, so the engine is probably coming out at some point. That seems like the most convenient time to deal with valves.
            1980 Suzuki GS850GT
            2011 Ducati Multistrada 1200
            1993 Honda XR650L

            Comment


              #7
              Hi there!

              Welcome in!

              I strongly believe all you'll ever need is in there: http://gsarchive.bwringer.com/
              Incredibly complete info on your bike.

              For your electrical problem, I'd check the coils first... --> http://gsarchive.bwringer.com/storag...dd-n-ends.html
              Then check if the black wires are getting to ground with the right timing. See the section Testing The Ignition System in the above document.
              Also worth mentionning is connections, of course. Most of my problems dispeared after a through out cleaning of the connectors.

              Good luck...

              Frank
              ------ Current rides: -----------------

              Honda CT70 K0 1970 complete restoration in progress
              Suzuki GS850 1979 as stock as could be... well except for the bars!
              Yamaha FJ-09 2016 with OEM saddle bags for long distance running and gunning
              Yamaha VStar 1300 2007 (wife's) for relaxing

              Comment


                #8
                Thanks Frank. A well thought out, step by step procedure is invaluable. I knew about BikeCliff's site, but hadn't drilled down that deep.
                1980 Suzuki GS850GT
                2011 Ducati Multistrada 1200
                1993 Honda XR650L

                Comment


                  #9
                  Originally posted by twerth View Post
                  I expect to have to replace some gaskets (maybe even the base gasket) before this is all over with, so the engine is probably coming out at some point.
                  There is no need to remove the engine to replace the base gasket. In fact, unless you have a way to stabilize the engine on a bench or a dedicated engine stand, I think it would be easier to replace the gasket while the engine is still in the frame. Everything necessary comes off easily enough in the frame. I have just replaced an engine in my 850 and can confirm this from experience, not just guessing.

                  .
                  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
                    Originally posted by Steve View Post
                    There is no need to remove the engine to replace the base gasket. In fact, unless you have a way to stabilize the engine on a bench or a dedicated engine stand, I think it would be easier to replace the gasket while the engine is still in the frame. Everything necessary comes off easily enough in the frame. I have just replaced an engine in my 850 and can confirm this from experience, not just guessing.

                    .
                    Good to know. But, I've got more than one reason to remove the engine. PO had "murdered" it out, so I want to disassemble as far as I can to get this thing cleaned up. I'm not afraid to drop an engine. Here's a shot of my Multi a couple of months ago when it had a crank bearing go bad.

                    2020-08-11 19.10.12.jpg
                    1980 Suzuki GS850GT
                    2011 Ducati Multistrada 1200
                    1993 Honda XR650L

                    Comment


                      #11
                      The technique that my son and I used to change my engine works rather well. It does require two people without major physical handicaps.

                      After removing everything that holds the engine to the bike (carbs, exhaust, wiring, mounts, etc.) the engine is just sitting on the frame. We used two ratchet straps as lifting slings. On the left side, the only practical attachment (on an 850) is the left rear, above the shifter. There is a hole where the airbox drain hose goes through. Place one hook there and hook the second hook of the same strap into the first hook. Loop the strap around the stator cover, then up, over your neck. The second strap can be hooked into holes in the crankcase that appear to be designed for this. One is in the front, one is at the rear. Place this strap over the second person's neck. Adjust the length of the straps so you are standing almost upright, but can still see the engine. Use your legs to lift and swing the engine to the right side a bit. You will have to move the left-side strap/sling to inside the frame rails while balancing the engine on the right frame rail, then move it again with the strap to the right of the frame and set the engine down on a dolly.

                      It probably sounds a bit harder than it actually is, but the two of us were able to easily remove the engine from my bike, then remove the engine from the parts bike and move it to my bike. One of the smaller Harbor Freight dollies will hold the engine well enough and it's easy to push around on the floor.

                      .
                      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


                        #12
                        Originally posted by Steve View Post
                        The technique that my son and I used to change my engine works rather well. It does require two people without major physical handicaps.

                        After removing everything that holds the engine to the bike (carbs, exhaust, wiring, mounts, etc.) the engine is just sitting on the frame. We used two ratchet straps as lifting slings. On the left side, the only practical attachment (on an 850) is the left rear, above the shifter. There is a hole where the airbox drain hose goes through. Place one hook there and hook the second hook of the same strap into the first hook. Loop the strap around the stator cover, then up, over your neck. The second strap can be hooked into holes in the crankcase that appear to be designed for this. One is in the front, one is at the rear. Place this strap over the second person's neck. Adjust the length of the straps so you are standing almost upright, but can still see the engine. Use your legs to lift and swing the engine to the right side a bit. You will have to move the left-side strap/sling to inside the frame rails while balancing the engine on the right frame rail, then move it again with the strap to the right of the frame and set the engine down on a dolly.

                        It probably sounds a bit harder than it actually is, but the two of us were able to easily remove the engine from my bike, then remove the engine from the parts bike and move it to my bike. One of the smaller Harbor Freight dollies will hold the engine well enough and it's easy to push around on the floor.

                        .
                        Wow, I wish you had that on video.

                        1983 GS750ED-Horsetraded for the Ironhead
                        1981 HD XLH

                        Drew's 850 L Restoration

                        Drew's 83 750E Project

                        Comment


                          #13
                          Got it running. The chassis ground for the wiring harness was almost nonexistent. I added a new ground wire from the harness ground directly to the engine and all is good. It fired right up. I don't have a headlight or tail lights, so there are still some electrical gremlins to figure out. I also installed the airbox, and it's evident that I need to spend some more time with the carbs.

                          That's ok though because I'm still a couple of weeks from being able to ride it (I'm on crutches at the moment). I'll keep chipping away and hopefully I'll have more progress to report by next weekend. With a little luck it'll be close to ready for a shakedown cruise.
                          1980 Suzuki GS850GT
                          2011 Ducati Multistrada 1200
                          1993 Honda XR650L

                          Comment


                            #14
                            Originally posted by jsandidge View Post
                            Wow, I wish you had that on video.
                            Me, too, but we were both rather busy at the time.

                            We might be talked into placing the (now)spare engine back into the parts bike, just for the video.

                            .
                            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


                              #15
                              Originally posted by Steve View Post
                              Me, too, but we were both rather busy at the time.

                              We might be talked into placing the (now)spare engine back into the parts bike, just for the video.

                              .
                              Please do. I've seen videos of several other methods. This one sounds much more interesting.

                              1983 GS750ED-Horsetraded for the Ironhead
                              1981 HD XLH

                              Drew's 850 L Restoration

                              Drew's 83 750E Project

                              Comment

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