running fork air pressure

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  • gearhead13
    • Feb 2026

    #1

    running fork air pressure

    I have been running about 10 psi pressure in my forks for a few years with the stock springs. I upgraded to progressive springs and let the pressure out and a few months later and my fork seals are leaking
    I am wondering if running some air pressure helps the seals, or is it just a coincidence?
  • hampshirehog
    Forum LongTimer
    Past Site Supporter
    • Oct 2007
    • 12675
    • Hampshire. UK

    #2
    It's just a coincidence. Or did you maybe overfill the forks?
    79 GS1000S
    79 GS1000S (another one)
    80 GSX750
    80 GS550
    80 CB650 cafe racer
    75 PC50 - the one with OHV and pedals...
    75 TS100 - being ridden (suicidally) by my father

    Comment

    • gearhead13

      #3
      Originally posted by hampshirehog
      It's just a coincidence. Or did you maybe overfill the forks?
      I believe I filled them with the proper amount, its been a few years since I rebuilt them. No leaks for 3 years or so then I let out the air pressure and soon after they are leaking. The forks were running lower with the new springs and no pressure, I wonder if that had something to do with it

      Comment

      • hampshirehog
        Forum LongTimer
        Past Site Supporter
        • Oct 2007
        • 12675
        • Hampshire. UK

        #4
        They shouldn't have run lower. Did you make up the spacer following the instructions with the new springs?
        79 GS1000S
        79 GS1000S (another one)
        80 GSX750
        80 GS550
        80 CB650 cafe racer
        75 PC50 - the one with OHV and pedals...
        75 TS100 - being ridden (suicidally) by my father

        Comment

        • gearhead13

          #5
          Originally posted by hampshirehog
          They shouldn't have run lower. Did you make up the spacer following the instructions with the new springs?
          The instructions said no spacer. They have adjustable preload at the top.
          I set them at the lowest setting, but have cranked it up two notches since.

          Comment

          • salty_monk
            Forum LongTimer
            GSResource Superstar
            Past Site Supporter
            Super Site Supporter
            • Oct 2006
            • 14003
            • London, UK to Redondo Beach, California

            #6
            Any rust spots in the near area on the fork leg? Maybe a small tear.... Do you run all year round? Maybe they dried out over the winter.

            Did you try running some very fine plastic (like a 35mm photo negative) around between the fork leg & the seal? Sometimes if there is a bit of crud there this cleans it out & they seal again.

            Unless you do no mileage a year 3 and a bit years may not be too bad for fork seals...

            OEM seals or aftermarket?
            1980 GS1000G - Sold
            1978 GS1000E - Finished!
            1980 GS550E - Fixed & given to a friend
            1983 GS750ES Special - Sold
            2009 KLR 650 - Sold - gone to TX!
            1982 GS1100G - Rebuilt and finished. - Sold
            2009 TE610 - Dual Sporting around dreaming of Dakar..... - FOR SALE!

            www.parasiticsanalytics.com

            TWINPOT BRAKE UPGRADE LINKY: http://www.thegsresources.com/_forum...e-on-78-Skunk/

            Comment

            • gearhead13

              #7
              Originally posted by salty_monk
              Any rust spots in the near area on the fork leg? Maybe a small tear.... Do you run all year round? Maybe they dried out over the winter.

              Did you try running some very fine plastic (like a 35mm photo negative) around between the fork leg & the seal? Sometimes if there is a bit of crud there this cleans it out & they seal again.

              Unless you do no mileage a year 3 and a bit years may not be too bad for fork seals...

              OEM seals or aftermarket?
              I ride it almost all year round. I bought the seals from Z1 I think, so probably K&L. Used K&L to rebuild my master cylinder too and haven't had a problem.
              I put about 9psi back in them, I'll ride it for a while and see what happens.

              Comment

              • salty_monk
                Forum LongTimer
                GSResource Superstar
                Past Site Supporter
                Super Site Supporter
                • Oct 2006
                • 14003
                • London, UK to Redondo Beach, California

                #8
                try the plastic trick... you might be surprised
                1980 GS1000G - Sold
                1978 GS1000E - Finished!
                1980 GS550E - Fixed & given to a friend
                1983 GS750ES Special - Sold
                2009 KLR 650 - Sold - gone to TX!
                1982 GS1100G - Rebuilt and finished. - Sold
                2009 TE610 - Dual Sporting around dreaming of Dakar..... - FOR SALE!

                www.parasiticsanalytics.com

                TWINPOT BRAKE UPGRADE LINKY: http://www.thegsresources.com/_forum...e-on-78-Skunk/

                Comment

                • gearhead13

                  #9
                  Originally posted by salty_monk
                  try the plastic trick... you might be surprised
                  Thats a good idea, but I would have to dig REALLY deep to find a photo negative So far no luck.
                  Trying to think of something else to use

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