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Loss of power around 5-6k RPM

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    #16
    Did you adjust the valves yet? Always good practice...
    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..... - FOR SALE!

    www.parasiticsanalytics.com

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

    Comment


      #17
      exzactly1 said...
      "Seems to struggle around 4.5-6k RPM depending on what gear I'm in"

      Could be ignitor or maybe the timing advance is stuck- remove signal generator cover and see if weights move freely.
      1981 gs650L

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

      Comment


        #18
        Originally posted by salty_monk View Post
        I had a faulty stock igniter on a 1000G that displayed similar symptoms. Chased it for ages thinking it was fuel related....

        Maybe your aftermarket ignition is doing the same... What ignition does it have on it?
        I'm not sure how to tell. The coils and wires are yellow; I can take a picture later maybe if that would help. Would it be printed somewhere on there?

        Originally posted by salty_monk View Post
        Did you adjust the valves yet? Always good practice...
        I have not done this yet. It's on my list. You're talking about the clearances right?

        Originally posted by tom203 View Post
        exzactly1 said...
        "Seems to struggle around 4.5-6k RPM depending on what gear I'm in"

        Could be ignitor or maybe the timing advance is stuck- remove signal generator cover and see if weights move freely.
        Is there a tutorial on the bikecliff site for this? I'm totally new to doing anything with the ignition system so I might need some more guidance here.

        Thanks guys.

        Comment


          #19
          Add one more thing to your check list:
          Make sure your needle jet's spacers/washers are in proper sequence. Pay particular attention to placement of thick plastic washer (#7) and thin metal washer (#36). Mine were swapped and caused the 5K rpm stumble you speak of... basically allowing needle to "flutter" under roll-on. You'll need ring pliers with long tines to remove the circlip (#10) to disassemble slides and thus check needle jets.

          Hope this helps.

          '80 GS1000ST
          '92 ZX-11
          Past rides: '79 GS1000SN, '84 GPZ900R

          http://totalrider.com/

          Comment


            #20
            Interesting, thanks Frank. I'll check that too next time I have the carbs off. I have not messed with those myself but perhaps another owner did.

            Comment


              #21
              Originally posted by exzachtly1 View Post
              I'm not sure how to tell. The coils and wires are yellow; I can take a picture later maybe if that would help. Would it be printed somewhere on there?



              I have not done this yet. It's on my list. You're talking about the clearances right?



              Is there a tutorial on the bikecliff site for this? I'm totally new to doing anything with the ignition system so I might need some more guidance here.

              Thanks guys.
              I suspect your COILS are ACCEL (given the yellow colour). This does not mean that your IGNITION trigger system is aftermarket though...
              If you remove the small right side cover (throttle side) and take a picture we'll be able to tell you if it's stock or otherwise. It's reasonably common for the stock ignitor's to go bad after 30 years so it may be that you need to get a Dyna S in there or something...

              There is a stock ignitor test in the Clymer manual that will tell you if it's faulty. You will need a multimeter.

              You may find your bike does not have mechanical advance (saw that suggestion posted above). I think they went to electronic advance in 82 on the G bikes.

              Valves - yes clearances.
              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..... - FOR SALE!

              www.parasiticsanalytics.com

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

              Comment


                #22
                Originally posted by salty_monk View Post
                I suspect your COILS are ACCEL (given the yellow colour). This does not mean that your IGNITION trigger system is aftermarket though...
                If you remove the small right side cover (throttle side) and take a picture we'll be able to tell you if it's stock or otherwise. It's reasonably common for the stock ignitor's to go bad after 30 years so it may be that you need to get a Dyna S in there or something...

                There is a stock ignitor test in the Clymer manual that will tell you if it's faulty. You will need a multimeter.

                You may find your bike does not have mechanical advance (saw that suggestion posted above). I think they went to electronic advance in 82 on the G bikes.

                Valves - yes clearances.
                Coils do appear to be ACCEL brand, it says that on the plug wires. Here is a pic of the ignition system.



                This is electronic, right? The PO did say that it had an aftermarket electronic ignition. I do not have a clymer manual; can someone explain the test? I do have a nice recently purchased multimeter but I have not really done any tests with it yet since I'm not totally confident in what I'm doing in that area.

                On my list:
                • Remove carbs. Check float levels and slide diaphragm assembly.
                • Attach vent hoses - these are missing but I have the OEM hoses now. Is it possible that this could affect performance at all? I've read some posts around the net stating that it could be a problem if these are missing or routed incorrectly...
                • Check valve clearances
                • Ensure good connection at airbox and check for leaks.
                • Test ignition system (need help here)

                I hope to get to some of this today, but the weather is nice so I might go for a ride instead and save all of this for a rainy day


                Hopefully this week I can report back with some results. In the meantime any help with the ignition testing would be appreciated. I'll also check the plugs and see how they look after my ride today.

                Comment


                  #23
                  Nice day- go for ride. Not aftermarket,that's the stock ignition setup (signal generator coils). Grab hex nut and twist clockwise- should move about 30 degrees and spring back smoothly when released. Remove seat, right above battery ,there are two electrical connectors. The one with just two wires - blue and green - is the one that connects to signal generator coils. disconnect this plug and measure resistance on wires running to signal coils (step 11 in the link below)

                  1981 gs650L

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

                  Comment


                    #24
                    It's rare that the triggers go bad unless the bike has had a spill... Usually the ignitor. The test involves energizing some of the connections with an AA battery.
                    You should be able to get a copy of the page specific to your bike, I don't have that.

                    I can't see from that pic if it has the mechanical advance... it looks like it but I can't be sure.
                    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..... - FOR SALE!

                    www.parasiticsanalytics.com

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

                    Comment


                      #25
                      Originally posted by salty_monk View Post
                      It's rare that the triggers go bad unless the bike has had a spill... Usually the ignitor. The test involves energizing some of the connections with an AA battery.
                      You should be able to get a copy of the page specific to your bike, I don't have that.

                      I can't see from that pic if it has the mechanical advance... it looks like it but I can't be sure.
                      Do I need to take the plate off to see that? Also, I tried turning it like tom suggested and it didn't seem to do any "springing back." It just kind of turned. I also watched it while the bike was running and revved the engine RPMs and it seems to move freely even at high RPM.

                      And for what its worth I checked the spark plugs and they looked good. Mostly tan colored.
                      Last edited by Guest; 10-08-2012, 03:27 PM.

                      Comment


                        #26
                        Took off the carbs and checked float heights, all were pretty spot on so I don't think that was the issue.

                        Here is the fiche for my Signal generator http://www.boulevardsuzuki.com/fiche...GNAL+GENERATOR

                        You're saying to turn it using bolt marked #6 in the fiche? When I tried that it did not spring back... Just kind of kept turning. Is that wrong?

                        I have a tappet tool, feeler gauge, and compression gauge in the mail so I will be checking valve clearances and compression soon. I haven't ruled out an air leak, ignition issues, or electrical issues... Just gotta find some time to get the manual out and learn how to take these readings. Im a total newbie with electric stuff.

                        Also think I will be ordering those airbox boots and clamps this week...
                        Last edited by Guest; 10-15-2012, 09:52 PM.

                        Comment


                          #27
                          Originally posted by tom203 View Post
                          Nice day- go for ride. Not aftermarket,that's the stock ignition setup (signal generator coils). Grab hex nut and twist clockwise- should move about 30 degrees and spring back smoothly when released. Remove seat, right above battery ,there are two electrical connectors. The one with just two wires - blue and green - is the one that connects to signal generator coils. disconnect this plug and measure resistance on wires running to signal coils (step 11 in the link below)

                          http://members.dslextreme.com/users/...-ends.html#A17
                          I'll start with this one when I do get to testing the electrics.

                          Comment


                            #28
                            Part #7 on that fiche locks into the spring loaded advance. See the two tabs on part #5?
                            It would be the one you want to test the springs with.

                            Comment


                              #29
                              Originally posted by koolaid_kid View Post
                              Part #7 on that fiche locks into the spring loaded advance. See the two tabs on part #5?
                              It would be the one you want to test the springs with.
                              Ah yes, thank you. Gotta grab a 19mm socket tomorrow and try that.

                              Comment


                                #30
                                This sounds EXACTLY like my problem. I have yet to tear into the airbox, but I think I'll be starting there along with checking the valves before I tear apart my freshly rebuilt carbs.
                                Last edited by Guest; 10-26-2012, 09:28 AM.

                                Comment

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