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p.o. Did this. Front shock spring?

Discussion in 'XJ Technical Chat' started by Carl LaFong, Apr 1, 2022.

  1. Carl LaFong

    Carl LaFong Member

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    Doing shock seals, found a 1 1/2 inch length of 1/2 inch galvanized steel pipe and washer on top of shock spring, both shocks? Measured spring it is 19 inches long. Is that stock length spring. Put 2000 miles plus on it last year, handled well with the stiffer spring mod. Keep it or not?
    Opinions? 1982 Sec a xj650rj
     
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  2. dwcopple

    dwcopple Active Member

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    Keep. I did it in previous bikes too. Great mod
     
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  3. Carl LaFong

    Carl LaFong Member

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    The length of the pipe in my shocks is 1 1/2 inches. Did guys use different lengths? Would like a little softer ride I am 165 lbs and ride rough roads . Thinking of shortening to say one inch? Thoughts welcome.
     
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  4. Jetfixer

    Jetfixer Well-Known Member

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    Back in the day this was THE mod , my local Yamaha dealer sold secas and maxims this was done many times he relayed to me to make front end stiffer.
     
  5. Carl LaFong

    Carl LaFong Member

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    I was wondering if the pipe that was used was always 1 1/2 inches long or were different lengths used. May shave off 1/2 inch using 1 inch pipe to soften ride on our rough roads.
     
  6. Fuller56

    Fuller56 Well-Known Member

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    Check the length of your springs as they may have been cut shorted as well. Some do that when stiffening via longer spacers.
     
  7. ManBot13

    ManBot13 Well-Known Member

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    Putting a spacer in the front shocks is for preload. It does not stiffen the suspension (although cutting the spring shorter, counter-intuitively, will stiffen it as Fuller56 said). But it changes how much load it takes for the suspension to start moving, and also affects ride height. Someone may have replaced the springs and they could have different rates than stock. I have replaced springs on several different motorcycles with race-tech straight rate springs (as opposed to the dual rate springs stock, or progressives) and tuned from there.

    PVC pipe can also be used, and washers can be added and removed to "tune" the preload. For the front suspension to work right, you want the right spring rate for the bike + you, and the proper preload. There are suspension tuners and sites you can use to calculate these as starting points.
     
  8. Simmy

    Simmy Well-Known Member

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    Stock length specified in my XJ650RJC manual is 21.28" so I suspect you have aftermarket springs, this is good.
    If they are Racetech then your spring and spacer combination should should be 3/4" longer than the fork.
    I mean you will need to compress this spring this much to get the fork cap on.

    I think this rule of thumb should work for other aftermarket springs, good starting point anyway.
     
  9. Carl LaFong

    Carl LaFong Member

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    Thanks for this. I reduced the length of the pipe to one inch. The pipe still stuck up above the shock top before compression. Will leave it like it is till next oil change or if it handles poorly. Gotta love this site!
     
  10. ManBot13

    ManBot13 Well-Known Member

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    This is normal with aftermarket springs. The spacer sticking up from the top cap just makes it a little trickier to thread properly, but reducing the preload too far will lower the front end and change handling. One inch could result in a serious reduction in available travel. Once assembled you can check the preload. In general, with you sitting on the bike, about 1/3 of the suspension travel (with the right spring rate) is a good starting point for preload.
     
  11. Carl LaFong

    Carl LaFong Member

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    Even with the spacer pipe reduced from 1 1/2 inches to one inch it was quite a job to reassemble. Had to use vice and c clamp. I will check the suspension travel when sitting on it. May be a while, got a few more things to do before weather decent and bike is up on table (harbour freight). Enjoy very much the input on this.
    side note: I almost bought a xj650 seca when they were new in 82, should have!
     

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