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Is it carbs or coils???

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    Is it carbs or coils???

    I am having a problem with either my carbs or coils on my 78 GS1000E. What is happening is that I will loose power and when the "defective" cylinder pipe is touched it is cold. More often than not the plug will be wet if it is removed. I have had the carbs rebuilt twice and am now running the Accel coil system for the points style ignition. The points are only a year old with very little time on them and now have been sanded clean as well. The last time I rode the bike I took a normal corner and just as I was coming out of the turn and starting to straighten up I heard and noticed that I had lost power again. It seems to be happening to number 3 cylinder most often, but has happened to number 2 and 4. Number 1 has never had any problems. I always seem to have spark at the plugs. So is it the carbs, coils or some other part of the ignition system.

    #2
    The quick answer is any of the above. If you are getting good spark, i'd look at how rish I am running those carbs. If you rebuilt them, and did not change jets or needle valve adjustment, check the float adjustment. Is your air filter clean? If your air filter is dirty it can choke it out as well. Make sure your enrichener rack is going all the way in too, I've seen one that was not put back on correctly and 3 of the 4 carbs ran with the enricheners out about 1/8 the way.

    At any rate i'd look for something making her rich.

    Tim

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      #3
      Originally posted by tbarnby
      , check the float adjustment. Is your air filter clean? If your air filter is dirty it can choke it out as well. Make sure your enrichener rack is going all the way in too

      At any rate i'd look for something making her rich.

      Tim
      Find out what's making her rich...then tell all of us, so we can get rich too!

      Seriously, Tim has almost certainly identified the problem as float level. Filters would not be intermittent, and having wet plugs despite good spark is a sure sign of too much fuel. The choke rack may be suspect, but you said it floods in the corners, so the problem will probably be floats.
      "If you scare people enough, they will demand removal of freedom. This is the path to tyranny."
      Elon Musk Jan, 2022

      Comment


        #4
        According to the Suzuki mechanic that performed the last rebuild, he said he had adjusted the float level to 23mm. The spec in my book says that the level should be between 23-25mm. I have not confirmed this. As for the air filter, it is clean, and white, no black areas at all. The choke rack seems to be fine, no binding or odd movement with it.

        Comment


          #5
          Just an off-the-wall thought...as the problem seems to come and go...how about a bad/intermittent ground in the electrics? I know before we did some work on Spouse-o-Mouse's bike (running a new ground for the regulator/rectifier and hardwiring some of the connections), we had what would have seemed to be carb problems...fixing the electrics at least partially cured that problem. Good luck. We know how frustrating it can be!

          Comment


            #6
            All the grounds that I could find have been cleaned and reinstalled. Will be starting to rewire the ignition wires from the points to the coils to the starter/kill switch later this week, hopefully to eliminate the electrical side of the problem. Also plan on running a couple of new ground wires from the battery to the frame and engine block, and since I am at it will wire new grounds to the regulator/rectifier. Thanks.

            Comment


              #7
              The float level may have been set, but you didn't say whether or not the float valves are seating correctly, which is critical. All of this should be part of the check, because if the valves don't seat perfectly then they won't shut off the fuel flow, which will cause a flooding situation.
              "If you scare people enough, they will demand removal of freedom. This is the path to tyranny."
              Elon Musk Jan, 2022

              Comment


                #8
                I would definately suspect the carbs. If it was the coils, #1 and #3 should go out together, since they share the same coil. It would have to be the plug wires for #3 to go out and not #1. Also, try some new plugs if they are at all old. Persistant fouling can't always be cleaned off and the plug will misfire under load, even tho they spark blue when you pull them out to test.

                Comment


                  #9
                  With this bike the left side coil controls plugs 1 and 4 while the right side coil controls plugs 2 and 3. #1 and #4 cylinders both reach top dead center at the same time, and #2 and #3 also reach top dead center at the same. The plugs are brand new, second set this year, trying to rule them out, and figure that I couldn't have two sets of plugs not working with the same cylinder. The coils are brand new as are the plug wires, and with the Accell coils you can cross the plug wires over to the other cylinder without hurting anything, as long as they are the from the same coil. So in this case I have tried to run #3 cylinder with either plug wire from the same coil and this had made no difference. #3 still doesn't work properly yet #2 will work properly with either wire. Are these bikes prone to having carb problems? What other types of carbs will work on this bike. If I can get my hands on some other working carbs I can then rule out if the problem is carbs or some form of electrical. Then I can focus on the real problem and not this guess work. Thanks

                  Comment


                    #10
                    I've got a very similar problem. Don't be suprised if the plugs are under 100km old and all fouled. I've had it happen in much less.

                    I thought it was oil leaking into the combustion chamber & rebuilt engine.
                    Stilll the same.
                    Replaced ignition system. Still the same.

                    Replaced carbs. Still the same.

                    Ensured sufficient shim clearance. Still the same.

                    Replaced virtually everything except replace wiring harness.
                    It's looking kind of guilty to me. I'm also finding it impossible to tune carbs satisfactorily. Whatever I do the plugs still foul.

                    I'm getting really sick of having to buy my sparkplugs in ten packs because I don't want to get caught without spares, It still happens but.

                    Could you let me know if the wiring work happens to fix your problems
                    please I'm keen to find what it is.
                    Trotski.

                    Comment


                      #11
                      Dead cylinder

                      Just a thought. It could be a plug wire?

                      Comment


                        #12
                        Re: Is it carbs or coils???

                        ok Ramnut I have the same bike as you (well i have the EC)
                        here is a thought for you
                        you may have a condenser with a intermitent break in it also have you checked the centrifigal timing advancer(it is behind the points plate) to see that it is working properly and freely because if it is not then you will experience a power loss as the RPM build because the timing is not getting advanced also check the points gap (14 thou) and the condition of the pionts but i suspect that it may be a combo of the advancer not working right and a condencer with a intermitant break
                        hope this helps you
                        Spyder Out

                        Originally posted by Ramnut
                        I am having a problem with either my carbs or coils on my 78 GS1000E. What is happening is that I will loose power and when the "defective" cylinder pipe is touched it is cold. More often than not the plug will be wet if it is removed. I have had the carbs rebuilt twice and am now running the Accel coil system for the points style ignition. The points are only a year old with very little time on them and now have been sanded clean as well. The last time I rode the bike I took a normal corner and just as I was coming out of the turn and starting to straighten up I heard and noticed that I had lost power again. It seems to be happening to number 3 cylinder most often, but has happened to number 2 and 4. Number 1 has never had any problems. I always seem to have spark at the plugs. So is it the carbs, coils or some other part of the ignition system.

                        Comment


                          #13
                          If there was any type of electrical problem it should affect both cyclinders that are connected to the same coil. Right? Two days ago after checking some wiring behind the headlight and repairing a small crack in the wire, the bike seemed to run fine on all cylinders. Yesterday I moved the bike (by hand) from my shed to the back yard started it up and now #4 cylinder pipe is cold yet in previous runs it was #3 cylinder. I do not think it is a electrical problem. With a timing light and looking at the timing marks you can see the plate move when the engine is reved up. If it is a condensor or points shouldn't both cylinders on the same coil be affected if they are at fault? Not just one cylinder at a time and then very seldom is it always the same cylinder. Quick note #1 cylinder has never ever had a problem it has always worked properly, knock on wood. I printed out the carb rebuild instructions from this web site, kind of looks complicated but may give this a try as well. Thanks for every ones replys to this problem. One of these months I will figure it out, probably just before snowfall, and then maybe I can give advice on such weird problems. Thanks again.

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