Ad Widget

Collapse

Announcement

Collapse
No announcement yet.
X

Fork Oils

Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • Fork Oils

    According to my haynes manual it says to use SAE10 Fork oil. However a friend of mine who has an 1980 GS 850 can use SAE10, SAE15, SAE20 and as a supplement can also use dexron ATF. Would the early katana 750's be able to handle the dexton ATF?
    1989 Suzuki Katana 750

  • #2
    You can go up to 15, I did.
    The oil is forced through ports to control the speed of the fork compressing/rebounding. Those ports are adjusted with the little dials on the end caps ( the 1-2-3)
    As you dial it up the post gets smaller and the oil
    can't get pushed though the ports as fast..
    By uprating the oil, this has the effect of making
    1 feel like 2 etc. So instead of 123 you have 234.

    Going to 20 would be like 345.
    Question is are your forks too soft?
    ("Bouncey")
    Or are they undersprung?
    (Bottoming out)
    Suzuki softened the springs for the Kat.
    So for sport riding they are undersprung.

    For the price, fork oil isn't very pricey.
    You don't change it often..
    ATF could work, but is it worth the experiment?

    Comment


    • #3
      I would only reccomend the dexton ATF for emergency use. MO
      TDA Racing/Motorsports
      1982 Honda CB750 Nighthawk, 1978 Suzuki GS750 1986 Honda CBR600 Hurricane; 1978 Suzuki GS1100E; 1982 Honda CB750F supersport, 1993 Suzuki Katana GSX750FP. 1981 Suzuki GS1100E (heavily Modified) http://katriders.com/vb/showthread.php?t=94258
      Who knows what is next?
      Builder of the KOTM Mreedohio september winning chrome project. I consider this one to be one of my bikes also!
      Please look at this build! http://katriders.com/vb/showthread.php?t=91192

      Comment


      • #4
        My forks do seem like they are undersprund. I feel like everytime I go over a big bump the forks dive too much in. Switching from 10 - 15 the forks would be stiffer right? (depending on what the dials are set up for).

        if they are boucny would that mean the oil needs replacement or that there is less than normal oil? its been 20,000km since the oil has been last changed.
        1989 Suzuki Katana 750

        Comment


        • #5
          check this out, for street use race tech says a 180 rider needs a .928kg/mm spring rate in the front and the factory is .629kg/mm rate stock.
          That is for a 89-97 750 Kat
          http://www.racetech.com/evalving/Spr...pringType=Fork
          TDA Racing/Motorsports
          1982 Honda CB750 Nighthawk, 1978 Suzuki GS750 1986 Honda CBR600 Hurricane; 1978 Suzuki GS1100E; 1982 Honda CB750F supersport, 1993 Suzuki Katana GSX750FP. 1981 Suzuki GS1100E (heavily Modified) http://katriders.com/vb/showthread.php?t=94258
          Who knows what is next?
          Builder of the KOTM Mreedohio september winning chrome project. I consider this one to be one of my bikes also!
          Please look at this build! http://katriders.com/vb/showthread.php?t=91192

          Comment


          • #6
            factory is set very low. im a light weight though, 165lbs, hehe. But I ride with a lot of gear all the time probably making it 190lbs.

            thanks for the help
            1989 Suzuki Katana 750

            Comment


            • #7
              Originally posted by 89katana750
              My forks do seem like they are undersprund. I feel like everytime I go over a big bump the forks dive too much in. Switching from 10 - 15 the forks would be stiffer right? (depending on what the dials are set up for).
              Springs weaken with time, and my suspicion is that you are still on the original springs -- on a 16 year old bike. Thicker fork oil will reduce the dampening, which means while your forks won't compress as much (because the oil will take more of the load), they also won't react to small bumps as well and the ride may turn harsh.
              KNOW THIS: because of the long wheelbase, heavy weight and sport-tourer design, the front end of a kat will normally dive far more under braking than a comparable true sports bike. This is intentional and designed that way to help reduce fatigue over long trips.

              Originally posted by 89katana750
              if they are boucny would that mean the oil needs replacement or that there is less than normal oil? its been 20,000km since the oil has been last changed.
              The oil should be replaced every other year under normal circumstances. Whether that 20,000km was in 3 months or 3 years is the important part, usually, unless there are damages to the oil seals (which would let it leak).

              Cheers
              =-= The CyberPoet
              Remember The CyberPoet

              Comment


              • #8
                Cyber what if you have the frontend off the ground alot?
                TDA Racing/Motorsports
                1982 Honda CB750 Nighthawk, 1978 Suzuki GS750 1986 Honda CBR600 Hurricane; 1978 Suzuki GS1100E; 1982 Honda CB750F supersport, 1993 Suzuki Katana GSX750FP. 1981 Suzuki GS1100E (heavily Modified) http://katriders.com/vb/showthread.php?t=94258
                Who knows what is next?
                Builder of the KOTM Mreedohio september winning chrome project. I consider this one to be one of my bikes also!
                Please look at this build! http://katriders.com/vb/showthread.php?t=91192

                Comment


                • #9
                  Originally posted by THAZKAT
                  Cyber what if you have the frontend off the ground alot?
                  See my response in this thread:
                  http://www.katriders.com/forums/viewtopic.php?t=3946

                  Cheers
                  =-= The CyberPoet
                  Remember The CyberPoet

                  Comment


                  • #10
                    I should have put a <laugh> behind that post sorry bro, and true that. So that explains alot about the weak fork springs and why the are dialed into a lite rider. Thanx Cyber
                    TDA Racing/Motorsports
                    1982 Honda CB750 Nighthawk, 1978 Suzuki GS750 1986 Honda CBR600 Hurricane; 1978 Suzuki GS1100E; 1982 Honda CB750F supersport, 1993 Suzuki Katana GSX750FP. 1981 Suzuki GS1100E (heavily Modified) http://katriders.com/vb/showthread.php?t=94258
                    Who knows what is next?
                    Builder of the KOTM Mreedohio september winning chrome project. I consider this one to be one of my bikes also!
                    Please look at this build! http://katriders.com/vb/showthread.php?t=91192

                    Comment


                    • #11
                      Originally posted by The CyberPoet
                      ... Thicker fork oil will reduce the dampening, which means while your forks won't compress as much (because the oil will take more of the load), they also won't react to small bumps as well and the ride may turn harsh...
                      Just as a clarification: Thicker fork oil will increase the damping (not dampening, sorry CP this is a personal peeve of mine). Thicker fork oil will stiffen the front end and make it less responsive (like CP explained).

                      Comment


                      • #12
                        Now im thinking of just sticking to the 10 wieght, I don't want the ride to be "harsh". Smooth was what I was going for.
                        1989 Suzuki Katana 750

                        Comment


                        • #13
                          Originally posted by tzortn
                          ...increase the damping (not dampening, sorry CP this is a personal peeve of mine).
                          Thanks... I actually appreciate that you've pointed that out to me in the past (and now), in as much as English is my second language; it's a mistake I make (and consciously thought about late last night -- as in "is it damping or dampening?" but just went with it).

                          Cheers
                          =-= The CyberPoet
                          Remember The CyberPoet

                          Comment


                          • #14
                            Originally posted by The CyberPoet
                            Thanks... I actually appreciate that you've pointed that out to me in the past (and now), in as much as English is my second language; it's a mistake I make (and consciously thought about late last night -- as in "is it damping or dampening?" but just went with it).

                            Cheers
                            =-= The CyberPoet
                            No problem. It is amazing how often that mistake is made. I hear engineers say it all the time.

                            Comment

                            Working...
                            X