Announcement

Collapse
No announcement yet.

Identifying forks, gsx750 or gs550?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Identifying forks, gsx750 or gs550?

    So I'm trying to find out what the forks on my gsx750E comes from, mainly to find how much oil to put in them.
    The closest thing I found to the suspension I have is those mounted on a gs550m katana:

    suzuki-gs550m-1981-x-e02-e04-e06-e22-e24-e34-front-right-damper-model-z_bigsue0051fig-49_2282.jpg

    Double spring, 2 position spring preload cap, 4 bolts anti-dive, 'ambient pressure'.
    Is it possible that someone mounted those on a 750, are all those forks interchangeable?
    I can't seem to find any reference of those forks used on a classic gsx750e.
    And finally does anyone know the oil level/oil amount to put in them?

    Ty,
    Federico.

    #2
    What year 750 have you got?
    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


      #3
      Should be a 82', 16 valves, round front lamp, European market.
      I don't think the forks are original.

      Comment


        #4
        Like this one?



        They had those type of forks. Good luck with trying to find out the fork oil capacity. I couldn't find it for my 1982 550ez and just plumped for the standard 140 mm level, forks fully compressed with no springs and that worked fine
        Last edited by hampshirehog; 05-06-2020, 02:52 PM.
        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


          #5
          Yes! that's the one. Thankyou, I've never been able to find the service manual for this version.
          I also seen many pictures of this bike (with the round lamp) but with forks without anti-dive, different markets?
          I'll do as you did and go for 140mm level, is that somewhat of a standard value?

          Comment


            #6
            140mm is kind of a rule of thumb value that I've used for years and I've seen others tote it around. I can't remember who told me but it seems to work.
            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


              #7
              From John Robinson's book "Service and setup data" Capacities/cc

              SAE 10/30 and ATF Pre 81 327, 81 210, 81 L 241 82 SAE15, 225 (cast wheels) 202 (spoked) 82 S 227 , 82 T 191 , 83 S 227 , 83 E, ES, SAE10 293

              I'd doubt the 10/30 and ATF spec is relevant now, probably SAE15 would work. Quite a variation between years and models.
              Robbo was good at sourcing thsi stuff.

              Comment


                #8
                mmm. Maybe Sae 10 is closer to the Multigrade+ATF mix? atf comes in at about 5-7w I think and the 10w30 would neet to get pretty hot to thicken...Funnily enough, Suzuki will call for the "mix" in some bikes while calling for "fork oil" in similar bikes of the same year.

                Yes, I often see 6" + for fork oil levels ...140mm (5.5") seems low but IS called for on some bikes.More oil shrinks the "compressible air space" but of course the volume of the actual leg is where the comparison might be made to find a general "airspace-compression" comparison...

                Comment


                  #9
                  I've always taken ATF to be around SAE 10. Seems to work out, anyway.
                  In the XJ, I just used a synthetic 5w40 and it works ok, too.
                  I've got loads of that particular 5w40 as it's not a long-lived oil for the engine, so a shelf full of it will keep my forks happy for years.
                  ---- Dave

                  Only a dog knows why a motorcyclist sticks his head out of a car window

                  Comment


                    #10
                    I don't know if the viscosity numbers are different for engine oil and fork oil, but I usually go with 10w fork oil.

                    The recomended level is usually in the 140-150 mm range.

                    .
                    sigpic
                    mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
                    hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
                    #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
                    #2 son: 1980 GS1000G
                    Family Portrait
                    Siblings and Spouses
                    Mom's first ride
                    Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
                    (Click on my username in the upper-left corner for e-mail info.)

                    Comment


                      #11
                      Thanks everyone,
                      for reference I ended up putting about 225-235cc with a level of 150mm.
                      Half a liter of oil is enough to fill both forks.

                      Comment

                      Working...
                      X