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Perplexing No Start Saga '79 GS850. Requesting your help!

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    Perplexing No Start Saga '79 GS850. Requesting your help!

    Hi all,

    I've got a 1979 GS850. Upon purchase, I rebuilt carbs, replaced o-rings, boots, fluids, adjusted valves, etc, etc, etc. I reckon a pretty thorough but standard going over. I set carbs to factory settings. It started up and, with the carbs set there, ran pretty good. I took it for a longer ride (50 miles or so) and, content with its performance, was ready to start on the aesthetic restoration.

    As of last fall, it never ran again. It just wouldn't start. I checked valve lash again and replaced spark plugs. I noticed weak spark. I didn't want to fuss with points anyway, so I purchased a Dyna ignition for it and installed it hoping that would be it. Still no start. Weak spark and after several episodes of troubleshooting with Dyna, decided that the ignition was faulty. So sent that in for warranty replacement. With the new ignition installed, still no start. Still pretty weak spark. It doesn't start on starting fluid, but I do get a weak exhaust backfire. Checked and adjusted timing, no change. Changed ignition coils with a spare set I have, still weak spark. Check, double check and re-check Dyna wiring, fuses, factory wiring. Added a new AGM battery as the old one was weak. Still no start, very occasional and weak exhaust backfire, weak spark.

    What am I missing? Help!
    Thanks!!
    1979 Suzuki GS850G The Michio Zombie: The Dead is rising and hungry for brains
    1980 Suzuki GS850GT, Collecting these things is a funny new bad habit

    #2
    Take seat off…find the 12v positive feed to ignition coils.. with key “on”measure voltage here before and then
    during starter cranking.
    1981 gs650L

    "We are all born ignorant, but you have to work hard to stay stupid" Ben Franklin

    Comment


      #3
      Ooh. Good reminder. Forgot to mention, that in all of this, I did the direct-to-battery/relay mod. Just went out and checked voltage with the new battery. 12.5v to the coils before, then ~11v to the coils with the starter cranking.
      1979 Suzuki GS850G The Michio Zombie: The Dead is rising and hungry for brains
      1980 Suzuki GS850GT, Collecting these things is a funny new bad habit

      Comment


        #4
        I reckon a pretty thorough but standard going over. I set carbs to factory settings. It started up and, with the carbs set there, ran pretty good. I took it for a longer ride (50 miles or so) and, content with its performance, was ready to start on the aesthetic restoration.
        As of last fall, it never ran again. It just wouldn't start.
        I hate these threads. WHAT could have changed? Where was it sitting?Your valves didn't just stop working because they sat awhile. More likely, Something You Did Since Last Running or, Old gas,dead battery (nope-done!) Kill switch corroded etc.. down the scale to less likely= Racoon picking lock and pooping in the tank.

        Comment


          #5
          Just for kicks, find a NON-resistor plug, any plug that will plug in to your plug cap should work, & check the spark with it, just holding it against the block, like you did with the resistor plug. Probably be the same, but I saw it happen, once...And it'd be a really cheeep, rule that out, test.
          1983 GS1100E, 1983 CB1100F, 1991 GSX1100G, 1996 Kaw. ZL600 Eliminator, 1999 Bandit 1200S, 2005 Bandit 1200S, 2000 Kaw. ZRX 1100

          Comment


            #6
            Originally posted by Gorminrider View Post
            I hate these threads. WHAT could have changed? Where was it sitting?Your valves didn't just stop working because they sat awhile. More likely, Something You Did Since Last Running or, Old gas,dead battery (nope-done!) Kill switch corroded etc.. down the scale to less likely= Racoon picking lock and pooping in the tank.
            Who doesn't hate these threads, right? Feel free to laugh at my expense and follow along. I feel it's something I've overlooked and the solution posted here may help someone someday.

            And for the record, the no-start situation happened overnight, with no molestations of any kind that I recall...in a locked garage with a watch-dog and watch-cat on site the likes of which would scare away all locksmithing varmints of any species. Seriously, this duo has absolutely decimated the rodent population on our 100 acre farm and is moving on to larger prey.
            Last edited by DesertRatliff; 05-12-2022, 01:07 PM.
            1979 Suzuki GS850G The Michio Zombie: The Dead is rising and hungry for brains
            1980 Suzuki GS850GT, Collecting these things is a funny new bad habit

            Comment


              #7
              Originally posted by rphillips View Post
              Just for kicks, find a NON-resistor plug, any plug that will plug in to your plug cap should work, & check the spark with it, just holding it against the block, like you did with the resistor plug. Probably be the same, but I saw it happen, once...And it'd be a really cheeep, rule that out, test.
              I am up for ALL kicks at this point!! Worth a try.

              I've got a whole mess of old spark plugs throughout the various shops on the farm here. How can I identify a non-resistor plug?
              1979 Suzuki GS850G The Michio Zombie: The Dead is rising and hungry for brains
              1980 Suzuki GS850GT, Collecting these things is a funny new bad habit

              Comment


                #8
                Not sure about all brands but usually an R in the number...NGK D8EA-non resistor DR8EA resistor etc
                1983 GS1100E, 1983 CB1100F, 1991 GSX1100G, 1996 Kaw. ZL600 Eliminator, 1999 Bandit 1200S, 2005 Bandit 1200S, 2000 Kaw. ZRX 1100

                Comment


                  #9
                  Speaking of resistor vs non resistor plugs, does that model have resistor caps? I had a resistor cap fail and testing my coils from plug wire to plug wire showed as a bad coil when in reality it was just the cap that was faulty.

                  Also, the other three caps were loaded with corrosion due to bad cap seals, along with corrosion where the wire connected to the cap.
                  Last edited by dorkburger; 05-12-2022, 02:01 PM.
                  sigpic
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                  Glen
                  -85 1150 es - Plus size supermodel.
                  -Rusty old scooter.
                  Other things I like to photograph.....instagram.com/gs_junkie
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                  Comment


                    #10
                    Whelp, looks like all of my sparkplugs are non-resistor type (on the '79, the '80 and 2 sets of spare in my box).



                    Also, I trimmed down the spark plug wires on all the coils I had for fresh, non-corroded copper and reattached everything.

                    What else could I be missing? Does not start on ether and ran fine before it didn't start so have ruled out fuel and compression so reckon it's gotta be spark. I'm pretty sure my static timing is set to at least start. But I am getting a soft exhaust backfire still so....
                    1979 Suzuki GS850G The Michio Zombie: The Dead is rising and hungry for brains
                    1980 Suzuki GS850GT, Collecting these things is a funny new bad habit

                    Comment


                      #11
                      Swapping the signal wires for the coils will produce backfires and prevent the engine from running.
                      Are you sure the coils are connected properly ?
                      Rijk

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                        #12
                        Forgot to mention, that in all of this, I did the direct-to-battery/relay mod
                        . Maybe get rid of that . for the moment, anyways.
                        and to add to simple good ideas above...
                        Check a plug or two for spark -replacing with a wee bit of fuel down the spark plug holes...
                        there's so many simple things to try that i forget half of them and kick myself when a 1/2 forgotten one works...fuse, kill switch...
                        Last edited by Gorminrider; 05-13-2022, 10:21 AM.

                        Comment


                          #13
                          Originally posted by Rijko View Post
                          Swapping the signal wires for the coils will produce backfires and prevent the engine from running.
                          Are you sure the coils are connected properly ?

                          Thanks for the response. I just went out and checked the wiring. The coils have two leads on each coil. There is an orange/white wire and a black wire on one and an orange/white and white wire on the other. Orange/white on both coils goes to 12v(+) from the relayed circuit to the (+) battery. White goes to white and black goes to black from the ignition so it appears everything is hooked up properly. For kicks, I switched the signal wires (the black and white) and there was no change; no start, no stumble, nothing.
                          1979 Suzuki GS850G The Michio Zombie: The Dead is rising and hungry for brains
                          1980 Suzuki GS850GT, Collecting these things is a funny new bad habit

                          Comment


                            #14
                            Originally posted by Gorminrider View Post
                            . Maybe get rid of that . for the moment, anyways.
                            and to add to simple good ideas above...
                            Check a plug or two for spark -replacing with a wee bit of fuel down the spark plug holes...
                            there's so many simple things to try that i forget half of them and kick myself when a 1/2 forgotten one works...fuse, kill switch...
                            Thanks. I'll try that. I remember adding the relay circuit in such a fashion that I could remove it and go back to stock if necessary without any re-re-wiring. I'll give that a shot. I remember trying a few different relays last Fall to make sure that wasn't it, but don't think I reverted to stock as it appeared the direct-to-battery mod was working as intended. Worth a shot reverting back at this point, though. I might just pull the carbs and at least go through them again to make sure they're not part of the problem. After all, I was troubleshooting all of this with a faulty (and new) Dyna ignition. I definitely need to retrace some steps now that I know that device isn't part of the problem.
                            1979 Suzuki GS850G The Michio Zombie: The Dead is rising and hungry for brains
                            1980 Suzuki GS850GT, Collecting these things is a funny new bad habit

                            Comment


                              #15
                              Seems at this point anything is worth a try. But if it won't start on starting fluid you'd think it must be the spark...I guess you won't know till you find it.
                              1983 GS1100E, 1983 CB1100F, 1991 GSX1100G, 1996 Kaw. ZL600 Eliminator, 1999 Bandit 1200S, 2005 Bandit 1200S, 2000 Kaw. ZRX 1100

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