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Mechanic says its time to let go of '81 GS750EX

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    Mechanic says its time to let go of '81 GS750EX

    Hey all,

    I bought my '81 GS 750EX in fall 2008. I've put about 10,000 miles on it (just over 28000 on the bike altogether) mostly commuting around town (Seattle). Aside from regular oil changes, spark plugs, chain maintenance, tires and brakes, I haven't done any work on it. It's been pretty reliable, and though I mostly stay off the road in the winter, I keep it garaged and manage to get out at least a dozen or so days during the rainy season.

    Last October I dislocated my shoulder (non-bike related injury) and didn't ride again until late spring. I had started it up a few times while I was rehabing the shoulder, but never got out and rode.

    When I took it out for the first time this spring, I got about 10 minutes from home, came to a stop sign and the bike died. It wouldn't start back up. I had a physical therapy appointment for the shoulder to get to, so I left it on the side of the road and came back an hour and a half later. It fired up and barely made it home before dying in the drive way. I drained the gas and put new gas in and checked the fuel filter, which appeared fine. The new gas seemed to do the trick. I rode every day for about two weeks. The idle seemed a little high but I wasn't too worried about it.

    And then about a week ago on a 90-degree day I went to start it up and it didn't want to start. When it did finally start, it sounded really rough - blatty, uneven. I started it yesterday and at first it didn't sound bad. I took it around the block and it started running rougher and rougher. It wanted to die when I came to a stop and to prevent it from doing so I had to give it a fair amount of gas. I was maybe 5 minutes away from home coming up a hill when it started sounding really terrible (blatty, again) and lost compression. No response from the throttle or choke. It died part way up the hill, and then wouldn't start again. It is still a few blocks over, and I'll be picking it up when my buddy shows up with the trailer in a few.

    Called a mechanic I've not dealt with before (Dan @ http://budgetcycleservice.com/) because my regular guy (Mike Lee of Maple Leaf Scooter) is MIA. (Anyone know Mike? Or heard from him? His phone is disconnected...). When I told Dan what was going on he said he wanted no part of it; said I was likely to end up owing much more than the bike's likely worth. Air leaks; float valve needles; carb cleaning; rust in the gas tank etc. etc. Last I checked the tank was clean, and the gas I drained back in May came out particle-free.

    I'm hoping that its just fouled spark plugs. I'm a ****-poor mechanic but I've done my own regular maintenance and I've got the Suzuki shop manual that came with the bike. I'm wondering how deep in the **** I might be. Any advice is welcome, and any second opinions that might confirm or contradict Dan's suggestion to move on to a new bike.
    Last edited by Guest; 07-11-2017, 08:02 PM.

    #2
    I hate lame @ss mechanics.

    Assess fuel and spark.

    Is fuel getting both to the carbs-and to the combustion chamber. If so, is it the correct amount?

    Is there spark to create combustion.

    It's probably time to check valve adjustment, too, and check the charging system for its health.
    Last edited by GS1150Pilot; 07-11-2017, 08:04 PM.
    "Thought he, it is a wicked world in all meridians; I'll die a pagan."
    ~Herman Melville

    2016 1200 Superlow
    1982 CB900f

    Comment


      #3
      Originally posted by GS1150Pilot View Post
      I hate lame @ss mechanics.
      He's just telling it like it is - many a time I've had to have the same conversation with people bringing non-running old bikes into our shop to make sure they realised they were probably going to have to empty their wallet to get their bike going again.
      Current:
      Z1300A5 Locomotive (swapped my Intruder for it), GS450 Cafe Project (might never finish it....), XT500 Commuter (I know - it's a Yamaha )

      Past:
      VL1500 Intruder (swapped for Z1300), ZX9R Streetfighter (lets face it - too fast....), 1984 GSX750EF, 1984 GSX1100EF (AKA GS1150)
      And a bunch of other crap Yamahas....

      Comment


        #4
        Welp, put the bike on the trailer and by the time I got to the house (maybe 10 minutes) THIS massive oil spill had pooled beneath it.

        There is no oil in the garage where I've kept the bike, and the quantity here suggests something catastrophic. I can't yet identify the leak and haven't pulled the plugs yet, but I wonder now if its even worth it, given the size of this oil slick that just poured out of it.IMG_1075.jpg

        Comment


          #5
          If it (the oil) smells like gas, it could be a failed petcock. Might explain some of the running issues as well.
          sigpic
          When consulting the magic 8 ball for advice, one must first ask it "will your answers be accurate?"

          Glen
          -85 1150 es - Plus size supermodel.
          -Rusty old scooter.
          Other things I like to photograph.....instagram.com/gs_junkie
          https://www.instagram.com/glen_brenner/
          https://www.flickr.com/photos/152267...7713345317771/

          Comment


            #6
            The oil does smell like gas. With the bike on the center stand, no more drips and nothing when I try to start it up. It did start, for a second, but as soon as I let off the gas it died. I'm starting with the fuel system and working down from there.

            Comment


              #7
              If the vacuum petcock fails, it will allow fuel to leak down the vacuum hose and into the cylinder then crankcase. Change the oil before moving forward. The oil level will be really high if gas drained into it, another tell tale sign of petcock failure.
              sigpic
              When consulting the magic 8 ball for advice, one must first ask it "will your answers be accurate?"

              Glen
              -85 1150 es - Plus size supermodel.
              -Rusty old scooter.
              Other things I like to photograph.....instagram.com/gs_junkie
              https://www.instagram.com/glen_brenner/
              https://www.flickr.com/photos/152267...7713345317771/

              Comment


                #8
                Originally posted by dorkburger View Post
                If it (the oil) smells like gas, it could be a failed petcock. Might explain some of the running issues as well.
                +1 Your petcock may have allowed fuel to enter your crankcase. The oil has gotten so thin that it can get past oil seals. Disconnect the fuel hose from the petcock and see if it is dripping. It .may not be as catastrophic as it sounds. A new petcock, oil and filter change and you may be good to go.
                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.

                Comment


                  #9
                  Hate to say it but 35 year old motorcycles are best owned by folks that wrench for themselves. I'd get something newer.
                  Ed

                  To measure is to know.

                  Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

                  Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

                  Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

                  KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

                  Comment


                    #10
                    Originally posted by gsrick View Post
                    +1 Your petcock may have allowed fuel to enter your crankcase. The oil has gotten so thin that it can get past oil seals. Disconnect the fuel hose from the petcock and see if it is dripping. It .may not be as catastrophic as it sounds. A new petcock, oil and filter change and you may be good to go.
                    Plus valve adjustment!
                    "Thought he, it is a wicked world in all meridians; I'll die a pagan."
                    ~Herman Melville

                    2016 1200 Superlow
                    1982 CB900f

                    Comment


                      #11
                      Originally posted by Nessism View Post
                      Hate to say it but 35 year old motorcycles are best owned by folks that wrench for themselves. I'd get something newer.
                      Truth..... however, if you're willing to listen and learn, this is the place.
                      sigpic
                      When consulting the magic 8 ball for advice, one must first ask it "will your answers be accurate?"

                      Glen
                      -85 1150 es - Plus size supermodel.
                      -Rusty old scooter.
                      Other things I like to photograph.....instagram.com/gs_junkie
                      https://www.instagram.com/glen_brenner/
                      https://www.flickr.com/photos/152267...7713345317771/

                      Comment


                        #12
                        Don't call a bike mechanic again unless you need a tire mounted or something. It's the petcock as has been said. Get a new petcock, change oil and see if it runs better. Run the seafoam or I like a heavy dose of Berrymans B-12 Cleaner (this is what you pour in tank) and get out and ride her.

                        Comment


                          #13
                          Originally posted by Nessism View Post
                          Hate to say it but 35 year old motorcycles are best owned by folks that wrench for themselves. I'd get something newer.
                          What he said. Most mechanics nowadays weren't even born when these bikes were around and if it isn't fuel injected and electronic they haven't got a clue.
                          '84 GS750EF (Oct 2015 BOM) '79 GS1000N (June 2007 BOM) My Flickr site http://www.flickr.com/photos/soates50/

                          Comment


                            #14
                            Originally posted by Nessism View Post
                            Hate to say it but 35 year old motorcycles are best owned by folks that wrench for themselves. I'd get something newer.
                            As others agreed; this is very much true.

                            Either you wrench, or spend.
                            #1: 1979 GS 550 EC "Red" – Very first Bike / Overhaul thread        New here? ☛ Read the Top 10 Newbie mistakes thread
                            #2: 1978 GS 550 EC "Blue" – Can't make it a donor / "Rebuild" thread     Manuals (and much more): See Cliff's homepage here
                            #3: 2014 Moto Guzzi V7 II Racer – One needs a runner while wrenching
                            #4: 1980 Moto Guzzi V65C – Something to chill

                            Comment


                              #15
                              Originally posted by roeme View Post
                              Either you wrench, or spend.
                              Sometimes you have to do both, but for a bike that has been dead reliable up until what is likely a failed petcock, I can't see anything majorly wrong happening, and it's not likely you are looking at a tear-down.

                              Do you have the space and time to work on it?
                              '83 GS650G
                              '83 GS550es (didn't like the colours in the 80's, but they've grown on me)

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