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    Spacer length? (Progressive Springs)

    Hello again friends and neighbors,

    I've got my new Progressive fork springs! \\/

    The kit came with a couple of washers and about an 8" length of heavy PVC-type pipe. I weigh about 200lbs, very little 2-up riding. How long should my spacers be in order to give me a firm but not harsh ride? About 2"? Thanks again for sharing your insight.

    Thank you for your indulgence,

    BassCliff

    #2
    Start off with about 2" spacers. Measure the fork fully extended with the wheel off the ground. Then measure again with the bike on the ground and your weight in the seat. When you end up with about 1 1/2" of sag you will be about right on the preload for the street. Sag is the difference between the two measurements. If you like a firm ride and do alot of canyon carving go for a little less sag. Set the rear of the bike up with the same amount of sag as the front.

    Comment


      #3
      Make sure when you cut the pipe that you don't have any angles. If you don't have a straight cut you will have no fun getting the fork caps back on.
      You might play around with the preload settings until you find a confortable one for you.
      1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
      1985 GS1150ES stock with 85 Red E bodywork.

      Comment


        #4
        I have 41mm in mine I think.... Be careful because Tom MLC's 1000 springs were different to my ones (although mine is a 1000G) although part numbers & forks etc are the same.

        The instructions tell you how to work it out anyway.

        I weigh 165lb but I didn't notice a lot of difference when I had it loaded up with kit for Yosemite....

        You probably won't want a lot more pre-load than me. I would go 2" max. You can always shorten it though I guess!

        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/

        Comment


          #5
          I'm 220lbs, I used 1.25 inches of preload. I don't think I could've got the caps on with any more. I like the ride. About 1 and a bit of sag. Plenty stiff enough. BTW: They seem to "wear in" after a bit. I have more sag now than before.

          Comment


            #6
            Cool man, cool. I can't wait to get these parts installed. Right now, if I don't use air my bike rides like a '67 Caddy. :-D

            Thank you all for your help.

            Thank you for your indulgence,

            BassCliff

            Comment


              #7
              Im a buck eighty and didnt use any, but I have preload adjusters on top of my forks. Dont you ? My preload & dampening are both on 2. No air and 15 wt oil. My progressive shocks on back have preload set on 2 and they have no dampening adjust.

              I dont do crazy in the corners anymore but this setup sucks up rough spots in the road pretty good.
              Last edited by bonanzadave; 08-14-2007, 09:31 AM.
              82 1100 EZ (red)

              "You co-opting words of KV only thickens the scent of your BS. A thief and a putter-on of airs most foul. " JEEPRUSTY

              Comment


                #8
                Originally posted by Billyboy View Post
                I'm 220lbs, I used 1.25 inches of preload. I don't think I could've got the caps on with any more. I like the ride. About 1 and a bit of sag. Plenty stiff enough. BTW: They seem to "wear in" after a bit. I have more sag now than before.
                Some of the increased sag is due to oil break down. Change it often for consistant performance.

                Comment


                  #9
                  Oil viscosity or breakdown affects damping, but does not affect sag.

                  Preload spacer length will vary considerably depending on which forks are on your bike, so unless you're certain that you're talking about the exact same model of bike, it's more productive to compare the total amount of initial compression, which will take into account the depth of the fork cap and the amount of spring showing above the fork, if any.

                  Here's how things ended up on my GS850G. Keep in mind that this is an extreme example. I am heavy (over 19 stone) and I ride quite rapidly. Most people should start with 25-40mm less preload spacer length, and test and adjust to taste.

                  Total spacer length I ended up with:


                  Amount this sticks up before squashing it down and screwing in the spacer. This is a nearly impossible task...lots of bad words and struggle.


                  The happy result: 25-30mm static sag (amount the suspension compresses with the bike upright and moi in the saddle):
                  1983 GS850G, Cosmos Blue.
                  2005 KLR685, Aztec Pink - Turd II.3, the ReReReTurdening
                  2015 Yamaha FJ-09, Magma Red Power Corrupts...
                  Eat more venison.

                  Please provide details. The GSR Hive Mind is nearly omniscient, but not yet clairvoyant.

                  Celeriter equita, converteque saepe.

                  SUPPORT THIS SITE! DONATE TODAY!

                  Co-host of "The Riding Obsession" sport-touring motorcycling podcast at tro.bike!

                  Comment


                    #10
                    That's 266lb for the uninitiated....

                    Picture 2 on mine was level with the top of the fork leg I 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!

                    www.parasiticsanalytics.com

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

                    Comment


                      #11
                      I'd heard there would be no math!

                      Thanks for doing the math Mr. salty_monk. 1 stone = 14 US pounds?

                      Thank you Mr. bwringer for the pictures. I love pictures!

                      Mr. bonanzadave, I haven't had my fork caps off yet, don't know what's under there. I've just been using air. We shall see.

                      Mr. emjay, thanks for the reminder to change my fork oil occasionally.

                      Thank you for your indulgence,

                      BassCliff

                      Comment


                        #12
                        If you can't see the preload adjusters from the top then you don't have them.... If like me you just have the air valves showing then that's all there is.

                        You can make an adjuster (basically a blanking plug cap with a bolt through it to move a large washer up & down) but it's probably OTT for what you need.

                        Work out the length to get it to the top of the forks & then add a max of 5mm for your weight if I was you.

                        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/

                        Comment


                          #13
                          Originally posted by salty_monk View Post
                          That's 266lb for the uninitiated....

                          Picture 2 on mine was level with the top of the fork leg I think.

                          Dan
                          Dang, I thought I was being obscure, but I forgot about all the Brits around here. #-o

                          Should've used slugs, drachms, or troy ounces.

                          I'm big and I'm fast. 'Nuff said.
                          1983 GS850G, Cosmos Blue.
                          2005 KLR685, Aztec Pink - Turd II.3, the ReReReTurdening
                          2015 Yamaha FJ-09, Magma Red Power Corrupts...
                          Eat more venison.

                          Please provide details. The GSR Hive Mind is nearly omniscient, but not yet clairvoyant.

                          Celeriter equita, converteque saepe.

                          SUPPORT THIS SITE! DONATE TODAY!

                          Co-host of "The Riding Obsession" sport-touring motorcycling podcast at tro.bike!

                          Comment


                            #14
                            Sorry! Let your secrets out

                            How are those Avons doing... I'm waiting to see what mileage you get before I decide on those or the demons!!
                            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


                              #15
                              Finally

                              Hi!

                              Wow, I can't believe how long it took me to actually install my Progressive springs. Did you notice how old this thread is? Since my seals were in good shape, no leaks, it was really easy to take off the forks, drain them, rinse them with mineral spirits, refill them and install new springs.

                              Here's a shot of the hardware coming out of the old fork. The stock spacer is 3" long.



                              I went with the documentation's suggestion of 1.75" spacer. I cut it and sanded it square. I would never have gotten that 3" spacer back in there.



                              Here's the old springs (top) and the new springs, to show the difference.



                              I ended up with 1.48" of sag. It's too late to go for a test drive. But I'll let you know.



                              That old oil was nasty! The new oil was a pretty red. I'll have a full write-up soon.

                              Thank you for your indulgence,

                              BassCliff
                              Last edited by Guest; 06-08-2009, 10:22 AM.

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