Dirrerence between air and non-air forks?

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  • tucker

    #1

    Dirrerence between air and non-air forks?

    Other than the obvious. I just picked up a set of forks for my '77 gs750 to do the single to dual disc change and the ones I just bought are air. How do they perform relative to each other? Also, how do the leading axle forks compare to the straight(?) forks.
    Thanks.
    tucker
    Last edited by Guest; 10-29-2008, 01:47 PM.
  • salty_monk
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    #2
    A lot of people get progressives or chop the springs so they don't have to run with the air...

    Leading axle forks are probably a little slower steering I would think.

    Dan
    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!

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    • focus frenzy

      #3
      the air is for preload adjustment. they tend to have a softer spring and rely on the air pressure to make up the difference, air air to firm up the front spring rate, lower it to make it softer.

      many prefere to use stiffer progressive springs or make preload spaces out of sch40 pvc pipe.

      the "L" model GS's used a leading axle fork to slow down the steering and give them a bit of a stretched look.

      there are a couple non L GS that used them also but generally it was done so that adjustable damping could be used as at the time the adjustment was via a knob on the bottom of the fork.

      a bit of trivia: the Yamaha 550 vision used a unusual trailing axle fork as they had to use a longer rake than desired so the forks would clear the radiator, moving the axle to the back side of the fork shortened the rake and made for quicker steering.

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      • Nessism
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        #4
        The spring rate for the air-assist forks is lower since Suzuki intended the use of air to bolster the metal spring. As Salty Monk stated, you can ditch the air completely if you get some Progressive springs or if you chop out some coils on the stock springs (replace the lost height with a PVC spacer). Just sticking a spacer in the forks without chopping the spring will increase the preload on the front end but it will not increase the spring rate - that's why chopping the springs is better.

        Oh, and the leading axle fork reduces trail which will make the bike steer faster (contrary to what many people think). Suzuki raked out the forks a degree for the L models, and added the offset fork to bring the trail back to the same as the STD models.
        Last edited by Nessism; 04-04-2009, 09:09 AM.
        Ed

        To measure is to know.

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        • Nessism
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          #5
          Originally posted by focus frenzy
          a bit of trivia: the Yamaha 550 vision used a unusual trailing axle fork as they had to use a longer rake than desired so the forks would clear the radiator, moving the axle to the back side of the fork shortened the rake and made for quicker steering.
          I had a Vision back in school. Very nice engine but handling was crappy. Trailing axle fork actually increases trail, which slows steering - not the other way around. Can't remember ever seeing another bike with a fork like that...maybe for good reason.
          Ed

          To measure is to know.

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

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          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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          • tucker

            #6
            I have a set of forks on a '79 GS850G I'm thinking of parting out, and I just bought a set of forks from an '81 750E with a leading axle. Would the '81 forks make my '77 a bit squirrely?

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            • salty_monk
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              #7
              I don't think any E model came with leading axle forks... Perhaps someone else fitted them later.

              Dan
              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/

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              • Nessism
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                #8
                The early 16v 750E and 1100E had leading axle forks. Not sure why but true story. The amount of offset is not that great so it shouldn't be a problem with installing this type of fork on an early 750.
                Ed

                To measure is to know.

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                • Guest

                  #9
                  keen to learn...

                  Originally posted by Nessism
                  Oh, and the leading axle fork reduces trail which will make the bike steer faster (contrary to what many people think). Suzuki raked out the forks a degree for the L models, and added the offset fork to bring the trail back to the same as the STD models.
                  does this mean that fitting L forks to the "standard" (non-L) steering stem would quicken the steering?

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                  • tkent02
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                    #10
                    Originally posted by psyguy
                    does this mean that fitting L forks to the "standard" (non-L) steering stem would quicken the steering?
                    Yes, if you don't put the gay "L" handlebars on it too.
                    http://img.photobucket.com/albums/v5...tatesMap-1.jpg

                    Life is too short to ride an L.

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                    • Guest

                      #11
                      Nessism: How much would I cut the springs and how long a spacer for my 80 1100 w/leading axle?

                      Paul

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                      • Nessism
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                        #12
                        Originally posted by nastyjones
                        Nessism: How much would I cut the springs and how long a spacer for my 80 1100 w/leading axle?

                        Paul
                        Hi Paul,

                        Try 3 inches for a start and see how the forks feel. You can always cut more if need be.

                        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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                        • tucker

                          #13
                          Is there any chance that the '79 GS850 fork lowers will swap with my '77 GS750B lowers and leave the air fittings on the upper tubes off my '77?

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                          • Nessism
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                            #14
                            Originally posted by tucker
                            Is there any chance that the '79 GS850 fork lowers will swap with my '77 GS750B lowers and leave the air fittings on the upper tubes off my '77?
                            750 forks are 35mm, 850 forks are 37's. Don't think parts swap between them.
                            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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                            • tucker

                              #15
                              So if I plan to use the 850 forks, I'll need to swap the tripples plus a bearing change? Or can I use them at all?

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