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A whole lot of problems all rolled into one!

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  • #1

    A whole lot of problems all rolled into one!

    So to start off, I have a 78 XS11. everything is stock as far as I know.

    The bike will start right up and idle nice at about 1000. When you pull the throttle it will start to rev up to about 1500 and then the bike will bog down and start to sputter. If you hold the throttle open the RPMs will climb very slowly. Once it hits about 5000 the bike will take off normally again, but if you hold the throttle up there it will again start to sputter and slow itself back down.

    Compression test: 1-110 2-110 3-80 4-90 (not looking good)

    Coils: Primary-3.3 at the TCI and 1.5 for each coil individually. I cannot get a reading got the secondary. I know I will at a minimum have to put new wires on the original coils, I just dont know how (help?)

    Hopefully tomorrow I am going to pull the valve cover off and check the valve clearance (what should I watch out for when I do this).

    What else should I be looking at/for?

    Thanks
    Nathan
    Nathan
    KD9ARL

    μολὼν λαβέ

    1978 XS1100E
    K&N Filter
    #45 pilot Jet, #137.5 Main Jet
    OEM Exhaust
    ATK Fork Brace
    LED Dash lights
    Ammeter, Oil Pressure, Oil Temp, and Volt Meters
    Green Monster Coils
    SS Brake Lines
    Vision 550 Auto Tensioner

    In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.

    Theodore Roosevelt
    Tags: None
  • #2
    Check the ignition advance in the left side crankcase cover, sound like it's sticking or the vacuum advance isnt working.
    1980 SG. (Sold - waiting on replacement)
    2000 XJR1300. The Real modern XS11. Others are just pretenders.

    Woman (well, my wife anyway) are always on Transmit and never Receive.

    "A man should look for what is, and not for what he thinks should be" Albert Einstien.

    Comment

    • #3
      Originally posted by b.walker5 View Post
      Check the ignition advance in the left side crankcase cover, sound like it's sticking or the vacuum advance isnt working.
      Ok, that will be one of the first things that I will do in the morning!
      Nathan
      KD9ARL

      μολὼν λαβέ

      1978 XS1100E
      K&N Filter
      #45 pilot Jet, #137.5 Main Jet
      OEM Exhaust
      ATK Fork Brace
      LED Dash lights
      Ammeter, Oil Pressure, Oil Temp, and Volt Meters
      Green Monster Coils
      SS Brake Lines
      Vision 550 Auto Tensioner

      In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.

      Theodore Roosevelt

      Comment

      • #4
        I know I will at a minimum have to put new wires on the original coils, I just dont know how (help?)
        The New Wires in Old Coils tech tip has a pretty good step by step. To give you an idea of how much material you actually have to remove from the coils, they should look something like this when you're done -

        I think I have a loose screw behind the handlebars.

        '79 XS11 Standard, Jardine 4/1, Dyna DC1-1 Coils, 145 mains, 45 pilots, plastic floats - 25.7mm, XV920 fuel valves, inline fuel filters, speed bleeders, Mikes XS pods, spade-type fuse block, fork brace, progressive fork springs/shocks, manual petcocks, 750 FD, Venture cam chain tensioner, SS brake lines

        Comment

        • #5
          This may sound silly, but did you hold the throttle open when you did the compression test.Because if you didn't you will have low readings.
          80 SG XS1100
          14 Victory Cross Country

          Comment

          • #6
            funny compression

            If you just got the bike and it has been in "storage" for a while, the compression numbers may actually improve after you ride it for a while.
            Skids (Sid Hansen)

            Down to one 1978 E. Stock air box with K&N filter, 81H pipes and carbs, 8500 feet elevation.

            Comment

            • #7
              I did not hold the throttle open, I can try it again doing it that way later.

              Yes I have only had the bike for about 2 1/2 weeks and it pretty much has not been used for about 12 years.
              Nathan
              KD9ARL

              μολὼν λαβέ

              1978 XS1100E
              K&N Filter
              #45 pilot Jet, #137.5 Main Jet
              OEM Exhaust
              ATK Fork Brace
              LED Dash lights
              Ammeter, Oil Pressure, Oil Temp, and Volt Meters
              Green Monster Coils
              SS Brake Lines
              Vision 550 Auto Tensioner

              In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.

              Theodore Roosevelt

              Comment

              • #8
                If you can, warm up the engine first just by ideling it. Then check your compression with WOT.
                '79 XS11 F
                Stock except K&N

                '79 XS11 SF
                Stock, no title.

                '84 Chevy K-10 "Big Blue"
                GM 350, Muncie SM465, NP208, GM 10 Bolt with 3.42gears turnin 31x10.5 Baja Claws

                "What they do have is an implacable, unrelenting presence and movement that bespeaks massive power lurking behind paint and chrome. They don't wail like a screeching ninja, the don't rumble like a harley. They just growl like a spactic, stressed out badger waiting to rip your face off and eat your soul." Trainzz~RIP~

                Comment

                • #9
                  If you can't get it warmed up, you can also try pouring a small amount of oil into each cylinder prior to testing. That will help the rings to seal about as well as their going to, and should provide a 'good' reading. Afterwards, it's going to smoke like you're fogging for mosquitos until it burns off the oil, but such is the price of accuracy .
                  I think I have a loose screw behind the handlebars.

                  '79 XS11 Standard, Jardine 4/1, Dyna DC1-1 Coils, 145 mains, 45 pilots, plastic floats - 25.7mm, XV920 fuel valves, inline fuel filters, speed bleeders, Mikes XS pods, spade-type fuse block, fork brace, progressive fork springs/shocks, manual petcocks, 750 FD, Venture cam chain tensioner, SS brake lines

                  Comment

                  • #10
                    Originally posted by natemoen View Post
                    I did not hold the throttle open, I can try it again doing it that way later.

                    Yes I have only had the bike for about 2 1/2 weeks and it pretty much has not been used for about 12 years.
                    Makes a huge difference with the throttle open while crsnking to check Compression.
                    "We are often so caught up in our destination that we forget to appreciate the journey." "

                    Comment

                    • #11
                      Originally posted by dbeardslee View Post
                      If you can't get it warmed up, you can also try pouring a small amount of oil into each cylinder prior to testing. That will help the rings to seal about as well as their going to, and should provide a 'good' reading. Afterwards, it's going to smoke like you're fogging for mosquitos until it burns off the oil, but such is the price of accuracy .
                      IMHO I do not agree with dumping oil into the cylinders prior to testing. It will always indicate a higher compression than what it would otherwise. It has nothing to do with accuracy and everything to do with fooling yourself. Your engine doesnt normally run with that much oil on the cylinder walls so why would you do that? Should I put some sawdust in my valve cover to quiet down the cam noise?
                      '79 XS11 F
                      Stock except K&N

                      '79 XS11 SF
                      Stock, no title.

                      '84 Chevy K-10 "Big Blue"
                      GM 350, Muncie SM465, NP208, GM 10 Bolt with 3.42gears turnin 31x10.5 Baja Claws

                      "What they do have is an implacable, unrelenting presence and movement that bespeaks massive power lurking behind paint and chrome. They don't wail like a screeching ninja, the don't rumble like a harley. They just growl like a spactic, stressed out badger waiting to rip your face off and eat your soul." Trainzz~RIP~

                      Comment

                      • #12
                        Originally posted by WMarshy View Post
                        Should I put some sawdust in my valve cover to quiet down the cam noise?
                        Hmmm... now theres a thought .LOL

                        But seriously the oil in the bore thing is an old school test to eliminate broken rings, and bad valves from the equation. First do your test dry, with WOT and then put a couple of cc's of oil in each bore and do it again. If you have leaking valves or broken rings the reading wont change much, if they all good the reading will be noticably higher. Never use oil for your first reading because as you've said, you'll get a false positive.
                        Last edited by b.walker5; 05-16-2010, 04:54 PM.
                        1980 SG. (Sold - waiting on replacement)
                        2000 XJR1300. The Real modern XS11. Others are just pretenders.

                        Woman (well, my wife anyway) are always on Transmit and never Receive.

                        "A man should look for what is, and not for what he thinks should be" Albert Einstien.

                        Comment

                        • #13
                          Your engine doesnt normally run with that much oil on the cylinder walls so why would you do that?
                          When the motor is running it's got plenty of oil on the underside of the rings, and it works it's way between them. When you let it cool down the oil is going to run away from the rings, and they won't seal as well. Putting a small amount in will compensate.
                          I think I have a loose screw behind the handlebars.

                          '79 XS11 Standard, Jardine 4/1, Dyna DC1-1 Coils, 145 mains, 45 pilots, plastic floats - 25.7mm, XV920 fuel valves, inline fuel filters, speed bleeders, Mikes XS pods, spade-type fuse block, fork brace, progressive fork springs/shocks, manual petcocks, 750 FD, Venture cam chain tensioner, SS brake lines

                          Comment

                          • #14
                            Update

                            I warmed the bike up and redid the compression test. new numbers were: 1-100 2-95 3-120 4-120.

                            I also pull the left cover off and was checking the vacuum advance. It seems to be moving freely. I watched it as I revved the motor and the advance moved with the RPMs. There was a little rust on the center rotating piece that I buffed off with some emery cloth. It seemed to be running a little better after I got rid of that little bit of rust (not sure if it had anything to do with that though).

                            Any other ideas or suggestions?

                            Nathan
                            Nathan
                            KD9ARL

                            μολὼν λαβέ

                            1978 XS1100E
                            K&N Filter
                            #45 pilot Jet, #137.5 Main Jet
                            OEM Exhaust
                            ATK Fork Brace
                            LED Dash lights
                            Ammeter, Oil Pressure, Oil Temp, and Volt Meters
                            Green Monster Coils
                            SS Brake Lines
                            Vision 550 Auto Tensioner

                            In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.

                            Theodore Roosevelt

                            Comment

                            • #15
                              May I offer a clarification please?
                              When conducting a compression test, the first test is performed 'dry' and the first reading is discarded (ambient air got in there when you pulled the spark plug out). WOT is not required, but it will get you to the max compression reading with fewer rotations and therefore less strain on the battery and starter (always remove all plugs for the test for the same reason).
                              The need for a 'wet' test comes into play if and when you find low compression on one or more cylinders, adding oil and retesting (again twice) will then give you insight as to where the loss of compression is originating.
                              The 'wet' test will always give higher results but if the results are only marginally higher the the "compression" is escaping through the valves (adding oil does not affect valve seating).
                              If it improves significantly then the rings are suspect.
                              If the engine in question has been mothballed for an extended period, then it needs to be operated for a few thermal cylcles (warmed up and cooled off) to 'reseat' both the rings and valves before a meaningful evaluation of performance can be obtained.
                              Hope this helps.
                              '78 E "Stormbringer"

                              Purrs like a kitten, roars like a lion, runs like a gazelle (being chased by a cheetah).

                              pics http://s1209.photobucket.com/albums/...tormbringer45/

                              Comment

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