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    Help me decide what to do first...

    The 83 1100E I just picked up runs pretty good, until I want to really stomp on it. It drives great when just crusing around, but if I open it up, I have a hard time getting over 100 (unless I am on the highway and I have a looooooong time). This bike has 15k miles on it, my 81 1100E has almost 45k and gets me over 100mph in a heartbeat. So what should I tear into first? Here is the background:

    The bike has K&N stage III jets and pods, and it seems set up pretty good. It starts hard, but don't all these old bikes? It's got a MAC 4 into 2 into 1 exhaust.

    It idles fine. The throttle response is pretty good. The carbs were recently synched. The plugs read perfect. Compression is good. In neutral, I can rev to the redline. In gear, I can rev high in 2nd or 3rd gear, but there doesn't seem to be enough high end horse power to rev to the redline in 4th or 5th!!

    So here are the things I think I should dive into:
    1. Float hights
    2. Clutch wear/slipping at high rpms (although I think I would know about it)
    3. Gas cap vent
    4. Fuel filter
    5. Petcock

    Can anyone suggest anything else? Am I wrong to think I have a fuel starvation issue here? I guess I'll have to add the timing to my list. How can I check/test the stock advancer?
    Currently bikeless
    '81 GS 1100EX - "Peace, by superior fire power."
    '06 FZ1000 - "What we are dealing with here, is a COMPLETE lack of respect for the law."

    I ride, therefore I am.... constantly buying new tires.

    "Tell me what kind of an accident you are going to have, and I will tell you which helmet to wear." - Harry Hurt

    #2
    sounds like GAS stavation at top end....could be as simple as a inline fuel filter that hasnt got eenough flow through....or the filter in the tap may be restricted

    Comment


      #3
      There is a filter in the tap itself? I didn't know that...
      Currently bikeless
      '81 GS 1100EX - "Peace, by superior fire power."
      '06 FZ1000 - "What we are dealing with here, is a COMPLETE lack of respect for the law."

      I ride, therefore I am.... constantly buying new tires.

      "Tell me what kind of an accident you are going to have, and I will tell you which helmet to wear." - Harry Hurt

      Comment


        #4
        Re: Help me decide what to do first...

        I believe the 83 was a non adjustable electronic ignition with electronic advance controlled through the ignitor box. My 85 1150 doesnt even have timing marks. (I have changed the ignition system and degreed/marked timing lines.)


        "The bike has K&N stage III jets and pods, and it seems set up pretty good. It starts hard, but don't all these old bikes? It's got a MAC 4 into 2 into 1 exhaust." ******** That may be the problem. Mac exhausts are aprox factory restriction. The intake system is modified to performance. Nothing has been done with the exhaust. For that setup, I would use no more than two increments over stock main jet size as a starting point.
        I think you are flooding the engine at full throtttle.

        "It starts hard, but dont all these old bikes?"........******* No, it should not. If it takes more than a quick touch to the starter button, its not right.
        They start instantly when the electrical, valves, timing and carbs are right.

        Earl


        Originally posted by Jethro
        The 83 1100E I just picked up runs pretty good, until I want to really stomp on it. It drives great when just crusing around, but if I open it up, I have a hard time getting over 100 (unless I am on the highway and I have a looooooong time). This bike has 15k miles on it, my 81 1100E has almost 45k and gets me over 100mph in a heartbeat. So what should I tear into first? Here is the background:

        The bike has K&N stage III jets and pods, and it seems set up pretty good. It starts hard, but don't all these old bikes? It's got a MAC 4 into 2 into 1 exhaust.

        It idles fine. The throttle response is pretty good. The carbs were recently synched. The plugs read perfect. Compression is good. In neutral, I can rev to the redline. In gear, I can rev high in 2nd or 3rd gear, but there doesn't seem to be enough high end horse power to rev to the redline in 4th or 5th!!

        So here are the things I think I should dive into:
        1. Float hights
        2. Clutch wear/slipping at high rpms (although I think I would know about it)
        3. Gas cap vent
        4. Fuel filter
        5. Petcock

        Can anyone suggest anything else? Am I wrong to think I have a fuel starvation issue here? I guess I'll have to add the timing to my list. How can I check/test the stock advancer?
        Komorebi-The light filtering through the trees.

        I would rather sit on a pumpkin and have it all to myself than be crowded on a velvet cushion. H.D.T.

        Comment


          #5
          No, it should not. If it takes more than a quick touch to the starter button, its not right.
          They start instantly when the electrical, valves, timing and carbs are right.
          Uh oh, that's not good. Here is the exact proccedure for getting my bike started:

          With full choke, I push the starter and she fires right up, then instantly dies. Then I keep full choke, crank the starter about 5 seconds while giving a little gas and it sort of bobbles to a start where I immediately back off the choke, keeping a tiny bit of throttle and then it idles perfectly with no choke or throttle. It's not that bad, but I guess you are saying that I might have a problem!

          Once I start it in the morning, I could keep it off for 8 hours and when I come back to the bike it will start immediately with no choke.

          Any suggestions?
          Currently bikeless
          '81 GS 1100EX - "Peace, by superior fire power."
          '06 FZ1000 - "What we are dealing with here, is a COMPLETE lack of respect for the law."

          I ride, therefore I am.... constantly buying new tires.

          "Tell me what kind of an accident you are going to have, and I will tell you which helmet to wear." - Harry Hurt

          Comment


            #6
            Yep, the petcock has a filter screen.

            Earl

            Originally posted by Jethro
            There is a filter in the tap itself? I didn't know that...
            Komorebi-The light filtering through the trees.

            I would rather sit on a pumpkin and have it all to myself than be crowded on a velvet cushion. H.D.T.

            Comment


              #7
              It could be a lot of things, but most likely, it is a small amount of error on a combination of things that cumulatively cause hard starting. When I tune my bike I check everything. You will never get an even plug burn adjusting the carbs if the voltage supply to the two coils is different.
              I check battery voltage, voltage to the coils, to the pickups and to the ignitor. I also check voltage using the engine ground. Something is wrong if at any point, the voltage drop is greater than 1/4 volt.I check valve clearances, timing and resistance on the coils and plug caps. I check charging current. If all of these are correct, then I can tune carbs. There is no point in even touching a carb until everything else is right. I synch the carbs precisely. A bubble off balance is not acceptable. Once the carbs are in synch, then I consider any jettting changes or needle adjustments. If I make any changes and/or adjust the idle mixture, I recheck the synch.

              Its the small stuff that will get you. :-)

              Earl


              Originally posted by Jethro
              Uh oh, that's not good. Here is the exact proccedure for getting my bike started:

              With full choke, I push the starter and she fires right up, then instantly dies. Then I keep full choke, crank the starter about 5 seconds while giving a little gas and it sort of bobbles to a start where I immediately back off the choke, keeping a tiny bit of throttle and then it idles perfectly with no choke or throttle. It's not that bad, but I guess you are saying that I might have a problem!

              Once I start it in the morning, I could keep it off for 8 hours and when I come back to the bike it will start immediately with no choke.

              Any suggestions?
              Komorebi-The light filtering through the trees.

              I would rather sit on a pumpkin and have it all to myself than be crowded on a velvet cushion. H.D.T.

              Comment


                #8
                When I tune my bike I check everything.
                Beautiful little troubleshooting/tuning schedule there, Earl.

                For anybody in doubt or looking to shortcut things, this should be REQUIRED reading. It sucks to have to be methodical and slow when all you want to do is ride, but it is the only way to get it truly right. And often, you find problems (or future problems) that you never knew about.

                Mark

                Comment


                  #9
                  Well, guess I should at long last learn how to use that fancy multimeter for something more than just continuity...
                  Currently bikeless
                  '81 GS 1100EX - "Peace, by superior fire power."
                  '06 FZ1000 - "What we are dealing with here, is a COMPLETE lack of respect for the law."

                  I ride, therefore I am.... constantly buying new tires.

                  "Tell me what kind of an accident you are going to have, and I will tell you which helmet to wear." - Harry Hurt

                  Comment


                    #10
                    It kind of looks that way. :-) My 1150 had been sitting in the shop for almost 3 weeks now waiting for parts. I know when I get the cylinders, head, etc back on it and set up the valvetrain, all I will have to do is turn on the petcock, wait 20 seconds for the bowls to fill, touch the starter, and it will be running before it has turned over twice and will instantly accept full throttle without a catch. Its nice when they run like that. :-)

                    Earl

                    Originally posted by Jethro
                    Well, guess I should at long last learn how to use that fancy multimeter for something more than just continuity...
                    Komorebi-The light filtering through the trees.

                    I would rather sit on a pumpkin and have it all to myself than be crowded on a velvet cushion. H.D.T.

                    Comment


                      #11
                      The second-best feeling in the world was when I finished rebuilding my 850, rolled it out of the garage, and it started instantly with the faintest tap on the starter button.

                      So yes, these bikes can and should start right away. If not, there's a problem.
                      1983 GS850G, Cosmos Blue.
                      2005 KLR685, Aztec Pink - Turd II.3, the ReReReTurdening
                      2015 Yamaha FJ-09, Magma Red Power Corrupts...
                      Eat more venison.

                      Please provide details. The GSR Hive Mind is nearly omniscient, but not yet clairvoyant.

                      Celeriter equita, converteque saepe.

                      SUPPORT THIS SITE! DONATE TODAY!

                      Co-host of "The Riding Obsession" sport-touring motorcycling podcast at tro.bike!

                      Comment


                        #12
                        A lot of bikes won't get within 1,000 rpm's of redline in top gear, level ground. The bike should not start hard though. Worn brushes would effect both cold and hot starts.
                        The advice of checking the electrical system is always good. It could have something to do with your acceleration problem, but I'm taking you literally about the perfect plug reads and other things you said such as the carbs are synched, etc.
                        So I think it's the re-jetting or dirty carbs. Are there other symptoms when you're accelerating to 100 like stuttering, bogging, etc?
                        Have you tried giving it choke while accelerating? If it helps, you're running lean. It also means your spark is handling the richer mixture and is a good sign of adequate spark.
                        If the choke hurts performance, then you're probably running rich.
                        Test and let us know what happens.
                        And on the seventh day,after resting from all that he had done,God went for a ride on his GS!
                        Upon seeing that it was good, he went out again on his ZX14! But just a little bit faster!

                        Comment


                          #13
                          Wow, that's an interesting test- I'll try it tomorrow.

                          There is no bogging or flat spots, maybe just a little poor throttle response. Otherwise it seems to pull smooth, but I should be able to get the bike to 100 without even trying. On my 81, when I wind her up and she gets spinning, it's like trying to hold onto a bull running from a bees nest.

                          I'm still thinking fuel starvation, but it might be wishfull thinking. I have no clue as to how to test the electrical system!

                          Earl?? Are you there?? Please help??
                          Currently bikeless
                          '81 GS 1100EX - "Peace, by superior fire power."
                          '06 FZ1000 - "What we are dealing with here, is a COMPLETE lack of respect for the law."

                          I ride, therefore I am.... constantly buying new tires.

                          "Tell me what kind of an accident you are going to have, and I will tell you which helmet to wear." - Harry Hurt

                          Comment


                            #14
                            It may very well be fuel starvation, but doing the choke test can narrow down possibilities. Fuel starvation and lean mixtures are seperate problems that are confused for one another.
                            And on the seventh day,after resting from all that he had done,God went for a ride on his GS!
                            Upon seeing that it was good, he went out again on his ZX14! But just a little bit faster!

                            Comment


                              #15
                              Ok, so I fiddled with the bike a little tonight and came up with some questions.

                              1. I want to add a better ground to my r/r. Whats the best configuration? Should I just make a lead between the housing and the negitive battery terminal? I don't want to fry that thing.

                              2. I re-checked all my plug reads tonight. All were a nice, dry mocha color. No carbon on the porcelin insulator. Yesterdays ride ended with a 45 mph throttle down the driveway, but as said in my post, I seem to be having problems with the top end. Should I hammer down the road, get her up to 90 and then hit the kill switch and read my plugs there on the road? Keith, I still haven't been able to try your choke test, but does it say anything that when warm, if I apply the choke the RPM's go way up? Shouldn't the bike die if I choke it while warm?
                              Currently bikeless
                              '81 GS 1100EX - "Peace, by superior fire power."
                              '06 FZ1000 - "What we are dealing with here, is a COMPLETE lack of respect for the law."

                              I ride, therefore I am.... constantly buying new tires.

                              "Tell me what kind of an accident you are going to have, and I will tell you which helmet to wear." - Harry Hurt

                              Comment

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