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Thread: Rear Shock Service/Re-build

  1. #11
    Senior Member Cooter's Avatar
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    That's very weird. Chicken is on the right track for sure.

    A shock re-build has nothing to do with pre-load. Pre-load/ sag is a matter of spring height. Period. The small caveat is you are going from zero nitrogen pressure in the junk shock you had to the 200psi (-ish) it should have had. It will affect height/spring rate slightly, but only slightly. And will only make it back to factory settings, not more. A hydraulic shock working, or not working can not affect the weight carrying capacity of the suspension (coil), their job is damping not carrying.

    The fact that the rear shock is working now will be a benefit for sure! The Buell settings are only meant as a starting point, and they should be the same even with RaceTech parts. Only RaceTech would know for sure, and it's worth asking them.

    Don't worry about whether you settings are in the middle or not. Crank them where you like them. If you get to where the settings are completely maxed out and still want more adjustment then you can make drastic changes like different coils and heavier oil. Then you get to start the adjustments all over again! Yay!

  2. #12
    Senior Member Cooter's Avatar
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    And check e-bay. I just bought a NEW rear XB coilover shock for $85 and he has more

  3. #13
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    Thanks Cooter, the PO was the Original owner and he weighs over 300lbs, his nickname is Shamu, and I still ride with him frequently. Shamu I think was a member here or on Badweather? He traded this Uly for a 2012 Tiger Explorer which he blew the rear shock out and wore out the replacement shock before he traded it in for a 2017 TE. So it is quite possible this Uly rear shock was out of nitrogen and low on oil when I acquired it and was the normal for me. Now that it has nitrogen it is foreign to me and I have to learn how to ride it again. Unfortunately I did not have the suspension knowledge to know the difference anyways, probably why I did a lot of cranking of the pre-load knob. Like you said, time to start over and make the adjustments, it has the stock spring so should be close to the original settings to start with. Thanks again.

  4. #14
    Senior Member Cooter's Avatar
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    "Shamu"... thats awesome At 300lbs he's big, but by no means over the bikes capacity. Most adventure bikes are fine with 2 riders and full gear, especially if the panniers are full too. He must ride it like an animal!

    I'd be curious to know what RaceTech says about their valves, if they are factory specifications or not.

  5. #15
    Senior Member Chicknstripn's Avatar
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    Do some google searching for "motorcycle suspension set up". You'll find all sorts of great info on setting static sag, rider sag and all sorts of stuff you probably never even thought about.
    Then google "buell xb suspension set up" and you'll find all sorts of info that is more directly related to your bike.
    Take it for ride after each adjustment and keep notes.
    You'll eventually find a good set up.

    BTW do you know if the forks have ever been rebuilt?

  6. #16
    Senior Member Cooter's Avatar
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    Exactly^^^^
    TBone, you sound like you ride hard enough (and are observant enough) to get it dialed.

    Simple notes: Do sag first, you have to get the bike level front and rear. You want to be at 1/3 up travel fully loaded (gear etc). Thin zip ties on the forks and shock shaft help measure that if you're doing this alone. They will also be a good telltale if you're running out of travel when riding it. Try keeping the compression as soft as you can without it bottoming out, and adjust re-bound for control. Too much re-bound and the bike will lower itself over multiple bumps and run out of travel too so be careful

    You mentioned the rear lifting with front brake application and I'll tell you that body position has more to do with that than suspension. Try this: Do a full hard stop using the front brake. Now do the same hard stop again but with totally loose arms, gripping the airbox cover with your thighs. Amazing right!?! Your whole center of gravity just dropped by 2 FEET!

  7. #17
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    Thanks for all the great input Cooter and Chicknstripn. Both Fork Legs are brand new replacements about January 2016.
    Tightened pre-load on forks to 5 turns in from Max Out and Cable tie is on the front fork and keeping it within %25 to %30 sag with my weight.
    Fork Rebound at 1 out from Max in, Comp. at 1 3/4 out from max in. Rear Pre-load is 0, Rebound at 1 1/2 out from Max in, Comp. at 2 out from Max in.
    "In" is clockwise "out" is Counter clockwise.
    Cooter thought about what you posted initially, how could the SAG change with the original spring and shock? My heels are 2 1/2" off the ground now, before the rebuild I was within 1" from flat footing.

  8. #18
    Senior Member Cooter's Avatar
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    Those settings sound about right for how hard you ride and the heavy weight (pillion) you have You can easily have 2 sets of settings for with and without a passenger. Me? I took off the rear pegs and covered the seat. She is welcome to come on her own bike

    Hydraulic shocks don't hold weight. If thats an accurate measurement, thats a big difference!! Like I said though, lets assume the shock was completely out of nitrogen, and now has about 200psi in it to reduce the oil aerating (as it should). What you have now (as the stock shock should) is a little extension force (not much) because the nitrogen pressure is slightly greater on the reservoir side of the piston because the shock shaft physical reduces the affective area of the piston on one side only.

    Fun fact:
    Thats why "gas shocks" extend them selves (not retract themselves or stay put).

    Funner-er fact:
    It's also why steering dampers have a shaft that extends through the whole body, not because they are pressurized (they aren't) but to make sure the forces are exactly equal in both directions.

  9. #19
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    Ok, think I understand. The nitrogen charge is increasing the oil pressure slightly more on the reservoir side of the piston, which is the top of piston as it sits on the bike. Is it possible that it can reduce the SAG on a ULY with a 200lb solo rider? Do you think it will settle down as I ride it more. I have about 150 miles on the shock now. I really am considering a spring plate or ring that appears to allow more SAG reducing the height a little.
    D72044F3-2F9F-4D03-B9B9-EF56DCEBFA8D[1].jpg
    I have seen a few spring plates and rings of r different sizes, some 15mm, 20mm, I think the one pictured above is about 25mm. Seems like I would not need much and a 10mm would be enough, if there is such a size?

  10. #20
    Senior Member Cooter's Avatar
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    I don't think it's enough of pressure to affect the total weight of rider and bike that much? Combining the weight of the rear of the bike and the ratio of the swingarm to lower shock mount (ahem, total guess) theres probably 700-800lbs of force on the rear coil to hold the static weight. We could use maths to figure the (200psiXpiston head)-(200psiXpistonhead-shockshaft diameter) for about +/-30lbs of downward pressure? (ahem, total guess). It's like putting a couple growlers in your saddlebag. will it lower the bike? Sure. Will you notice?

    Edit:
    And you can find out exactly how much the lowered coil cover will lower the bike without guessing.
    you need the the loaded coils height (or shock eye to shock eye)
    The ratio between the swingarm pivot to axle (s) divided by the swingarm pivot to lower shock mount (m)

    use that ratio to know how far the axle will move for a given reduction in shock height (15mm...20mm whatever)
    Boom! Mathed! hahaha


    Last edited by Cooter; 09-01-2017 at 03:46 AM.

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