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Thread: Fork spacers........

  1. #1
    Registered User Jinxman69's Avatar
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    Fork spacers........

    So I just reassembled the forks from my 74 R 90/6 and the manual says to place the " spacer " onto the top cap and screw the cap down into the top of the fork. I didn't have a spacer in there to begin with. Is the spacer used to adjust sag? I'm 230lbs fully geared up. I imagine I should find some spacers and install them. So I will sacrifice a little travel. I think firming up the front would be a good thing.......opinions........

  2. #2
    Monza Blue 1974 R90/6
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    I use pieces of PVC pipe. I forget the exact "sag" that you should shoot for, someone else will chime in with correct # and link to the procedure.

    Basically, you mark height of upper fork area/handlebars with you off the bike and then again with you on the bike. Difference, or "sag", from memory, is something like between 1" and 2".

    Keep increasing the length of the PVC spacers on top of the spings until you get the sag into the desired window.

    Barron

  3. #3
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    You have a wide range here, 35-45mm. I assume you're using the stock springs; you'll have better luck with Progressive or RaceTech springs. RaceTech has different rate springs available and a calculator for rider weight. I like the ones on mine.
    61 Gold Star, 76 R90S, 03 CBR600RR, '13 690 Duke, '14 Street Triple R

  4. #4
    P Monk
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    spacers?

    My bike had progressive springs and pvc spacers. It did not ride well. I bought R90S springs and cut a little off of the spacers, but it still didn't ride very well.
    The R90S springs are longer than the progressives and have some compression without a spacer. Just did a rebuild on the fork legs and went with R90/S springs with no spacer. This combo is the best ride I have gotten yet. It handles well and ride is much improved. BTW I am not a lightweight.
    P. Monk
    74 R90/6 (also know by bride as the Black Hole). 09 R1200 GS. My wife, 1953 model who has survived aplastic anemia and a bone marrow transplant.

  5. #5
    not lost til out of gas 128521's Avatar
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    I used pvc pipe cut with a tube cutter and metal washers on both ends. I had progressive springs also, tossed them and got Race Tech springs rated for my weight, and added a gold valve, on both sides, Ohlins in the back. I have been thrilled with the results. Race Tech has a book, the suspension bible, which will tell you more than you ever wanted to know about suspension.
    don't know where I'm going, but I'm making good time. 1990 R 100 GSPD, 2005 R 1200 GS

  6. #6
    Monza Blue 1974 R90/6
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    Quote Originally Posted by 128521 View Post
    ... and added a gold valve, on both side ....
    But, I think with the forks on the R90 bikes from the OP there are some additional modifications required to the fork internals (brazing some of the holes closed or drilling some additional holes, can't remember which) if you go to the Race Tech emulators? And the jury is still out as to whether the emulators really make a significant difference in that model forks?

    Barron

  7. #7
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    Quote Originally Posted by barron_williams View Post
    But, I think with the forks on the R90 bikes from the OP there are some additional modifications required to the fork internals (brazing some of the holes closed or drilling some additional holes, can't remember which) if you go to the Race Tech emulators? And the jury is still out as to whether the emulators really make a significant difference in that model forks?

    Barron
    Well, you need at least 6 for a jury, but this one says they make a significant difference and work very well on forks of this vintage. And it's drilling additional holes.

    http://forums.bmwmoa.org/showthread....ght=gold+valve
    61 Gold Star, 76 R90S, 03 CBR600RR, '13 690 Duke, '14 Street Triple R

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