GS750T will not start

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • cloudbreakmd
    Forum Sage
    Past Site Supporter
    • Jun 2005
    • 2404
    • Bethesda, Maryland

    #1

    GS750T will not start

    So Duane came down the week before last and we worked on the bike.
    The cams were out of time, so they were removed and reinstalled.
    Timing was checked with a light. Coils are brand new, spark plugs are brand new, fuel and petcock also brand new.
    But the bike will not start. It cranks over as it should but not even a cough of life.
    Starting fluid was greeted with one (yes only one) backfire through the airbox. Now there is no response from the starting fluid.
    There is spark across all 4 spark plugs.
    The ignition advancer was also removed, inspected, cleaned and reinstalled.
    Compression is good across all 4 cylinders as well.

    Quoted from Duaneage (from the temporary board):
    We checked the timing three times with the valve cover off. The 1-4 mark including the T and F marks were up and the camshafts were right where they should be. 10 plates, 20 pins between the marks. Just like the manual. We had 140+ lbs of compression. FWIW we swapped the coil wire pairs back and forth and no change. Definitely plenty of spark.

    I suspect the carbs but incredibly bad weather kept us from trying that the last night I was there. I would use a spare set of carbs known to exist near this bike and try them. I don't think the choke system is working properly on the carbs he has. He can still swap coil wires around if need be
    2010 Honda VFR1200F
    1983 Suzuki GS750T (sold)
    Being Revisited
    1981 Honda CM400T
    http://www.bikepics.com/members/cloudbreakmd/
  • UncleMike

    #2
    If you haven't dipped the carbs and installed fresh rubber as well as made sure all the valves are in spec, that should be first on your list.

    Or you could just buy my 750T. It's running PERFECTLY and it's for sale...

    Comment

    • Guest

      #3
      Is the igniter good?
      Is the crank trigger facing the right direction?
      Humor me and switch the trigger to the other direction.

      Comment

      • trippivot
        Forum Sage
        Past Site Supporter
        • Aug 2006
        • 2815
        • Des Moines , IA

        #4
        how is the ignition timing??

        heck if you have the carbs off of the head and shoot starting fluid in there while cranking you'll get it to run unless the spark is happening at the wrong time. period going off of your description

        engine in time mechanically --check

        compression 140? --check

        Fuel --- not that important if you use ether

        spark on all 4

        spark at the right time 1-4 and 2-3 non (oil or fuel) fouled plugs etc..

        pow!!! you should have life all you need are 3 components

        1.compression 2.fuel 3.timed ignition

        don't let the plugs fool you I have seen good appearing plugs be the source of many running problems. they are cheap get another set and try again.

        a plug may fire out in the open but sometimes under the pressure of the combustion chamber they won't light up. Ive seen that too. weird but true
        SUZUKI , There is no substitute

        Comment

        • Nessism
          Forum LongTimer
          GSResource Superstar
          Past Site Supporter
          Super Site Supporter
          • Mar 2006
          • 35766
          • Torrance, CA

          #5
          I managed to get the cams 180 degrees out on one bike I was working on. It's easy to do since the timing marks will seemingly line up. I suggest you look at the magnetic trigger on the rotor and make sure it's pointing at the proper 1-4 trigger when cylinder #1 is at TDC.

          Won't hurt to check.

          Good luck.
          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

          • cloudbreakmd
            Forum Sage
            Past Site Supporter
            • Jun 2005
            • 2404
            • Bethesda, Maryland

            #6
            Sighs... I hope it's not timing again.
            I'm hoping Duane will chime in because he remembers the details better than me, I'm sure.
            2010 Honda VFR1200F
            1983 Suzuki GS750T (sold)
            Being Revisited
            1981 Honda CM400T
            http://www.bikepics.com/members/cloudbreakmd/

            Comment

            Working...