990 Shock Stretch

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by sama3033, Nov 22, 2012.

  1. sama3033

    sama3033 Been here awhile

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    I know, I know! there are a million threads on this topic but I've just finished stretching and revalving my forks so now it's back to the man-cave and on to the shock and there doesn't seem to be as much discussion about that and a I wondered why. If anyone knows of a shock specific thread I'd be grateful if you could point me at it. I have the necessary parts - I just want to be sure there are no pitfalls or surprises in disassembly and rebuild.

    Happy Thanksgiving All

    SM
    #1
  2. knobbyjoe

    knobbyjoe Adventure and dirt rider

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  3. Bronco3738

    Bronco3738 Mike

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    In case you don't realize it the shock is under high pressure nitrogen. Most people don't do their own shocks because they don't have the equipment to refill the nitrogen charge.

    Good luck I'd like to see a write up of the shock rebuild.
    #3
  4. sama3033

    sama3033 Been here awhile

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    Yeah, I'm aware of that little detail but Racetech has a work-around that I'm eager to try. I'm one of those experiential learners - learn by doing and if I fuck it up I keep trying until I get it right. The forks were interesting and I learned a lot about fluid dynamics in the process - this is cool stuff in my mind. I'm taking my time and enjoying myself. I'm thinking of building CF safari tanks next. Wish me luck.
    #4
  5. Konflict Motorsports

    Konflict Motorsports KM TUNER

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    Sama
    What is your weight, and how much do you carry and riding style? Aggressive, mild? Where are you riding the bike, and how much on road to off road?
    Id be happy to give you a few tips and stacks.
    #5
  6. sama3033

    sama3033 Been here awhile

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    Konflict my friend - I bought the spring for the stretch from you and have the rebound shim provided by Superplush (not sure how it differs from stock but we'll find out soon). Racetech valve and shims should be here any minute.

    I'm right around 200lbs. Riding style is varied, 70% on-road, but I do ride fairly aggressive off road when I can (NJ Pine Barrens which vary between hard-packed gravel and foot deep sand) Sandblast a while back (DEEP ruts, more sand, a lot of lying on my back, insane fun!)

    Grateful for any input

    SM
    #6
  7. Bronco3738

    Bronco3738 Mike

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    Glad to hear you are going forward on the shock.

    I can't wait to see the thread on the tanks. Do you know what resin you are going to use that is fuel proof, and how do you plan on making the fuel cap? I've worked with carbon before but never on tanks. There is a thread on here from Pete640 who made some very nice side tanks, maybe give you some ideas.

    And again Good Luck.
    #7
  8. Capt.saveaho

    Capt.saveaho Been here awhile

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    I don't know about the 990 rear shock but I know on mx bikes there is a peening on the shaft for the valve stack to prevent the nut from coming off, that would require grinding. Good for you taking on this task, once I figure out what needs changing on my forks I am going to do it myself as we'll.

    Also when you mean stretch, you mean increasing the travel?

    +1 talk to James at superplush, 9X0's are his specialty. He won't hesitate to tell you what you will need, and honestly you may only need a spring or a preload spacer the rear is way better setup then the front.
    #8
  9. sama3033

    sama3033 Been here awhile

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    I found this thread here too. It's a really nice primer on how to lay up not-so-easy shapes in carbon; a CF/kevlar Suzuki SV tank. Really nicely done by Tygaboy - I'm going to follow his lead.
    #9
  10. sama3033

    sama3033 Been here awhile

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  11. sama3033

    sama3033 Been here awhile

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    I've already completed the forks and there's a tiny bit of grinding to do there before you can get to the compression shim stack but it's nothing and only requires some Locktite on the threads when rebuilding. I had a lot of fun with this by the way and learned a lot in the process. The biggest problem I had was reseating the compression valve assembly and getting it torqued to the right specs because it will just spin if you cannot get a proper grip on the rebound shaft.

    The only problem I foresee with the shock is the nitrogen but it may just be a matter of getting my local shop to recharge it afterward. Live and learn.

    SM
    #11
  12. Konflict Motorsports

    Konflict Motorsports KM TUNER

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    Sama,
    When reinstalling the base valve into the cartiridge the stand process is to extend the cartridge rod and pull it to one side of the upper fork tube. This well eliminate the lower cartridge spinning while reinstalling the base valve.
    As for the WP Adventure unit, it does not have any peening on the nut. It will make it very easy for you to swap out the pistons and valving.
    #12
  13. sama3033

    sama3033 Been here awhile

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    Konflict

    Yeah I had to do some jiggling with the compression valve before realizing that pulling the rebound to one side was the ticket but I was nervous about bending something and having it be out of true. It was all good in the end but it took some time and effort. If I had all the pro tools it obviously would have been easier. The sense of accomplishment is huge.
    #13