81 gs 450l questions

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  • 03svrider

    #1

    81 gs 450l questions

    i have an 81 gs450l i bought with 12071 on the clock. it now has almost 13000. the engine seems to ping a little when i'm getting on it. i put regular in it but filled it with super last night to hopefully solve that issue. when do i need to adjust the valves? i'm thinking soon because of the milage so i'll plan on doing it over the winter but i'm wondering if the pinging could be from needing a valve adj. the engine sounds great when it's running. no valve taps, the thing runs like a top!
    also. sorry to ask too many questions. the brake lever almost comes to the bar when i squeeze it initially but if i give it a quick pump before i plan to brake it is pretty solid. old master cylinder or air in the line?
    thanks for any input.
  • Nessism
    Forum LongTimer
    GSResource Superstar
    Past Site Supporter
    Super Site Supporter
    • Mar 2006
    • 35788
    • Torrance, CA

    #2
    By all means, do the valve adjustment ASAP. Don’t be lulled into complacency by the fact that the engine is running well, tight valves will cause them to burn, particularly the exhaust valves. Tight valves will not however cause the engine to detonate, or ping. Run the higher grade of fuel and maybe check the ignition timing (not sure it’s adjustable though). Also, check the advance weights as well to see if they are stuck which will cause the timing to be off.

    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

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    • 03svrider

      #3
      in the clymer there is no mention of weights. it says the ignition is electronic so i guess there are no points to adjust. could you elaborate? also, know anything about the brake lever question from the original quote? thanks alot.

      Comment

      • kb9lae

        #4
        My 450 runs fine (no ping) on 87 octane and it is all stock, in fact I have tried using premium fuel and didn't notice a differance in performance and my mileage was worse. If you look under the "points cover" there should NOT be points. It should just be electronic, kind of like the underside of a distributor cap "rotor and two tabs". Just make sure those pieces are clean, if not try a little sandpaper or emery cloth to clean them. They sometimes tend to collect moisture in their and corrode a little.

        As far as the brakes go you are on track. The only way to be sure would to try flushing first to see if that fixes the issue. Maybe some dirt is restricting the fluid or like you said air in the lines. Then go from there check your pads, cyclinder, caliper etc...

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        • Nessism
          Forum LongTimer
          GSResource Superstar
          Past Site Supporter
          Super Site Supporter
          • Mar 2006
          • 35788
          • Torrance, CA

          #5
          Originally posted by kb9lae
          If you look under the "points cover" there should NOT be points. It should just be electronic, kind of like the underside of a distributor cap "rotor and two tabs". Just make sure those pieces are clean, if not try a little sandpaper or emery cloth to clean them. They sometimes tend to collect moisture in their and corrode a little.
          Yes, electronic ignition but with mechanical advance. The rotor is movable and attaches to two spring loaded weights which move out with rpm. I'm not sure the best way to check them but they must not be stuck.

          Brakes pumping up are often the result of air in the system. The brake fluid should be changed about every two years so if you haven't done it lately, now is a good time. Of course, if there is chunkies in the fluid a full teardown is in order. If this does not help you may want to replace the brake line since it may be expanding. Braided stainless lines make the lever much firmer.

          Hope this helps.
          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

          • Guest

            #6
            When I play with my jetting and it's lean it will ping.
            Are you trying to pull the bike hard at under 3000 rpm? This will also cause pinging.
            Are the carbs clean, petcock screen clean, fuel line good, running a inline fuel filter, air filter oiled or stock, vent lines clear, fuel cap vent clear and valves adjusted?

            Comment

            • 03svrider

              #7
              thanks everyone. i put super in it and the pinging is almost nonexistant but over the winter i plan on doing fork oil, valve check, etc. so i'll look into the other possibilities then.

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