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Cylinder 1 and 4 not firing?

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    Cylinder 1 and 4 not firing?

    GS1100GL. I have checked the coil and the primary end reads 5 ohms and secondary reads 30k ohms which is spec. I have checked for spark and it’s firing. Sometimes I get 3 hot. cylinder 4 will get hot then cylinder 1 stays cold. Last time I checked 4 didn’t fire. Bike has 11,500 miles. I’ve put marvel mystery oil in gas to see if it helps any over time. Does anyone have any info to troubleshoot? Or experienced the same issue?
    Last edited by Guest; 05-03-2018, 05:18 PM.

    #2
    Originally posted by baesorenson View Post
    I have checked the coil and the primary end reads 5 ohms and secondary reads 30 ohms which is spec. I have checked for spark and it’s firing. Sometimes I get 3 hot. cylinder 4 will get hot then cylinder 1 stays cold. Last time I checked 4 didn’t fire. Bike has 11,500 miles. I’ve put marvel mystery oil in gas to see if it helps any over time. Does anyone have any info to troubleshoot? Or experienced the same issue?
    What bike? It may be your signal if you have an electric ignition or the points for 1-4 may be out of adjustment if you have points.
    GSRick
    No God, no peace. Know God, know peace.

    Eric Bang RIP 9/5/2018
    Have some bikes ready for us when we meet up.

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      #3
      Sorry 82 GS1100GL

      Comment


        #4
        It may be co-incidence that 1 and 4 are not firing, but spark is only part of the issue why they might not be getting warm.

        You say you have 5 ohms on the primary and 30 ohms on the secondary. Unless you have mis-typed or mis-read your meter, you have a problem. You should have about 30K ohms on the secondary.

        Have you checked valve clearances and cleaned the carbs? Either one of those can also contribute to a cylinder not firing enough to get warm, even though the spark is firing.

        Because 1 and 4 share the same coil, it sort of automatically leads you to think it might be electrical, but don't rule out the other possibilities until you have actually checked them.

        .
        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.)

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          #5
          Yes 30K. Which is by the book. I have not took the valve cover off yet to check clearances. Carbs are cleaned with new stock jets.

          Comment


            #6
            valves can cause a dead/intermittent cylinder.
            1983 GS 1100 ESD

            Comment


              #7
              Just checked valves and the clearance is as follows:

              cylinder 1
              intake- 0.04 mm was tight but went through didnt have a .03mm
              Exhaust- 0.05mm

              Cylind r 2
              Intake- 0.05mm
              Exhaust- 0.04mm

              Cylinder 3
              Intake- 0.06mm
              Exhaust- 0.04 did not fit (again i don't have a 0.03mm size)

              Cylinder 4
              Intake- 0.06
              Exhaust- 0.04 did not fit either

              With that said i realize that cylinder 3 and 4 exhaust shim is more than likely out of spec but doesn't seem to be the issue of why cylinders 1 and 4 are not firing...

              Comment


                #8
                Do the simple stuff first...remove spark plug caps, cut plug wires back 3/8 inch, reattach caps or consider new caps (about $5 each). Clean the connections from signal coils,ignitor, and up to ignition coils.
                Has this critter been sitting awhile? If yes, proper carb cleaning is on your to do list. These carbs don't like ethanol fuel hanging around theire innards
                1981 gs650L

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

                Comment


                  #9
                  Originally posted by tom203 View Post
                  Do the simple stuff first...remove spark plug caps, cut plug wires back 3/8 inch, reattach caps or consider new caps (about $5 each). Clean the connections from signal coils,ignitor, and up to ignition coils.
                  Has this critter been sitting awhile? If yes, proper carb cleaning is on your to do list. These carbs don't like ethanol fuel hanging around theire innards

                  I’ve rebuilt the carbs with new jets and blew air down every hole I have cut wires and rescrewed cap on. I checked the coil and it’s reading fine on both ends. I checked spark plug for spark. I checked valve clearance and only have cylinder 3 and 4 exhaust tappers needs adjusting. Now I have to order new valve gasket to start bike back up because old one was trashed.

                  Comment


                    #10
                    Ok, you got spark...onto carbs
                    If you didn't either dip the carbs or use a ultrasonic cleaner before blowing air at them, you likely have forced crud into the tiny passages that the idle circuit uses to supply mixture to carb throats. Tooling around your neighborhood, you'll be running mostly on these idle circuits...if some pipes aren't hot, their cylinders are probably starved.
                    1981 gs650L

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

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                      #11
                      I’ll pulled the carbs off again and recheck everything. Would not having the air box on the bike cause this issue? I didn’t put them on as I was just testing the bike to see if it would run.

                      Comment


                        #12
                        Originally posted by baesorenson View Post
                        I’ve rebuilt the carbs with new jets ...
                        Hopefully you did a bit more than just slap some new jets in there. And, hopefully you did not use the jets out of a "rebuild kit". Too many times, those jets are of questionable quality. It's better to clean and re-use the original jets.


                        Originally posted by baesorenson View Post
                        Would not having the air box on the bike cause this issue? I didn’t put them on as I was just testing the bike to see if it would run.
                        The bike will start and idle without the airbox, but don't expect any throttle respose to get above idle speeds. The part that scares me is "them" when you are referring to the airbox. Do you actually have the stock airbox or are you using individual pod filters? Yes, it makes a difference, as pods will require different jetting.

                        .
                        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


                          #13
                          I went to Suzuki Dealer and he said K&L jets are same as stock. Which the sizes were the same. Wouldn't understand why 2 carbs would work and other 2 won't...

                          Yes bike idles fine and boggs with power over 3k rpm. Not trying use power. I just let it idle to see if all are firing. I refurbished airbox with weatherstripping and new Uni foam filter. I should have said "IT". Sorry, I am not using pods.

                          I should have done a compression check before taking valve cover off to inspect valve clearance. Now I have to get new gasket before next turn over. But with my valve clearance measurements still doesn't make sense why 1 and 4 aren't firing... Coil reads within spec, Spark plug is sparking, Intake Valve clearances on all 4 are within spec. Only cylinder 3 and 4 exhaust valve could use adjusting. Leaves me thinking i just need to put valve cover back on and do a compression check. If 1 and 4 is low then may need new rings. If compression is good then nothing to do but pull carbs off again and re clean and install I guess..

                          Comment


                            #14
                            Most likely plugged pilot jets. Under the rubber plug. You did replace the rubber plugs, right?
                            sigpic
                            09 Kaw C14 Rocket powered Barcalounger
                            1983 GS1100e
                            82\83 1100e Frankenbike
                            1980 GS1260
                            Previous 65 Suzuki 80 Scrambler, 76 KZ900, 02 GSF1200S, 81 GS1100e, 80 GS850G

                            Comment


                              #15
                              yes everything is new in carb except diaphragm and needle which were in good condition and cleaned.

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