Fox DHX Coil making loud whoosing noise??- Mtbr.com
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  1. #1
    check your six
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    Fox DHX Coil making loud whoosing noise??

    O.k.,.. I will try this post in the DH/FR forum. I figured I would have some luck posting it in the Shocks / Suspension forum, but no one replied. If anyone can offer some advice I would appreciate it much. Below is the origional post.
    -Thanks

    ------------------------------
    Hey all,
    I have a quick question before I make the call to FOX. I have a new 08' Bottle Rocket with a DHX coil. I have had it for about 4 months and rode the bike quite a bit, but not nearly as much as I should. Today, I took her off the wall and went to pedal around the block and I noticed the shock makes a very loud whooshing noise when compressed and uncompressed. The noise really happens when the shock is uncompressing. The shock has never made this loud noise before, in fact it was suprisingly quiet from the beginning. It sounds like there is air / oil that is making the sound squirting around in there somewhere. It is actually very loud. It is way louder then the 66 RC2X on the front. I know that the zoke forks make this sound slightly and that is normal. (I think)

    However, when I sit on the bike and bounce on it, compressing and uncompressing the shock to make the noise, the piggy back or resivour actually gets a bit warm fairly quickly. Again, the noise is very loud too. I tried letting all the air out of the boost valve, dialing the pro pedal all the way out, and starting the set up over from scratch. After I finished setting the shock up, 150psi in the chamber, pro pedal dialed two clicks from firm, and the noise it still there. The shock does not feel any different from what I can tell, just the odd noise and the warming of the resivour.

    Is this normal? Could there be something wrong? Am I just being paranoid? I just don't want to make any issue worse by riding it until I am sure. Any help on this would be extrememly helpful.

    Thanks
    - Sodak
    "We can always find excuses if we want to find them, but if we really want to do something, we have to just go."

  2. #2
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    I'm no expert by any means,but I have a BR with dhx and no noises like that. I think you may need to bleed the damper, sounds like you may have air in it.
    Team _________

  3. #3
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    Quote Originally Posted by rollertoaster
    I'm no expert by any means,but I have a BR with dhx and no noises like that. I think you may need to bleed the damper, sounds like you may have air in it.
    Uh.. ohh.. That sounds "not-good". Any ideas of how to blead the damper? How would one get air in the damper? Do you think I might have done something wrong to it on set up to cause this?
    "We can always find excuses if we want to find them, but if we really want to do something, we have to just go."

  4. #4
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    I'm affraid I don't know how. I've got a blown one in my garage that I haven't gotten around to taking apart yet. I'm sure someone on here knows how.

    I don't think it's your setup I haven't had any problems on mine and I've had it for over 2 years now.
    Team _________

  5. #5
    check your six
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    Cool... Thanks for the info. I will wait patiently for more info from this thread. It is still new, so worst case, I guess Fox could help me out. Thanks again!
    "We can always find excuses if we want to find them, but if we really want to do something, we have to just go."

  6. #6
    BrassBalled DropbarNinja
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    you could try burping out the air or do a rebuild with the shock in oil...
    Last edited by mrpercussive; 08-05-2008 at 08:55 AM.

  7. #7
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    Thanks for the help guys! I called Fox this morning and explained the issue. The rep told me that there was most likely oil in the boost valve. Not sure how this exactally happened. The Fox manual is so damn vauge regarding set-up. The only this it says to to never run the shock with less than 125psi or over 200psi or so. I have always had 150psi in the boost vavle??

    So, since this shock is new, and I am not a confident tinker-er on suspensions (forks or shocks), I got an RA number and am going to send it off to them. Now to find that damn reciept... Sucks that I will be off the Bottle Rocket for awhile. Ohh.. well. This is my first Fox product after jumping off the Zoke band wagon..... not sure if it was such a good idea...
    "We can always find excuses if we want to find them, but if we really want to do something, we have to just go."

  8. #8
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    Send it in

    Doesn't sound good... perhaps it is time to contact either fox or the folks at push to service your shock. At least push could custom tune it for you if you choose that route.

  9. #9
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    Bleeding shocks is easy.

    Follow the directions on this site- http://happymtb.org/forum/read.php/1/661268/

    Essentially, all you have to do is disassemble the shock, pull the IFP, and then reassemble the shock under an oil bath so that there is no air in it, and then reset the IFP to the right height.

  10. #10
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    i have done that twice with my fox shock first time i sent it away to fox and they replaced all oil and seals for free and the seond time well its gone now wo waiting for a verdict. but also the first time it did it it was very lund then on the way home it vented all of its oil so inturpit that your own way, i would have a look inside your shock if you know how to take it part properly (unlike me note sending it away)
    Quote Originally Posted by [Orge
    ]
    This problem could quite simply be solved if people would stop buying Konas.

  11. #11
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    Quote Originally Posted by sodak06
    The only this it says to to never run the shock with less than 125psi or over 200psi or so.

    The range is 75psi-200psi. you are not supposed to adjust the bottom out control over 125.

    Both my dhx's make a little bit of noise on high speed hits, not sure if there is air in the system but they both feel great

  12. #12
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    Quote Originally Posted by bustanutley
    The range is 75psi-200psi. you are not supposed to adjust the bottom out control over 125.

    Both my dhx's make a little bit of noise on high speed hits, not sure if there is air in the system but they both feel great
    Minimum boost valve pressure on 2008 DHX's is 125psi, not 75psi.

  13. #13
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    08 gottcha didn't know they changed, thanks for the correction, cheers

  14. #14
    Big Test Icycles
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    My 08' BR / DHX 5.0 made that noise when it was brand new. It turned out to be that the rebound was set way to slow, I gave it a few clicks and that sound went away, no issues since.

  15. #15
    check your six
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    Quote Originally Posted by dowst
    Bleeding shocks is easy.

    Follow the directions on this site- http://happymtb.org/forum/read.php/1/661268/

    Essentially, all you have to do is disassemble the shock, pull the IFP, and then reassemble the shock under an oil bath so that there is no air in it, and then reset the IFP to the right height.

    You make it sound so easy.. I checked out the link you gave and I am now more intimidated than before. Since the shock is new and under warranty I am going to send it in. Next time I might just give the tear down a shot! Thanks for the info!
    "We can always find excuses if we want to find them, but if we really want to do something, we have to just go."

  16. #16
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    Quote Originally Posted by sodak06
    You make it sound so easy.. I checked out the link you gave and I am now more intimidated than before. Since the shock is new and under warranty I am going to send it in. Next time I might just give the tear down a shot! Thanks for the info!
    Haha it's intimidating at first, but once you get into it it's very straightforward.

    If it's under warranty though, without a doubt send it to Fox.

  17. #17
    N* Bomber Crew
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    Quote Originally Posted by sodak06
    This is my first Fox product after jumping off the Zoke band wagon..... not sure if it was such a good idea...
    Good idea. DHX's are dope as hell.

    Fox has good turnaround too.
    Northstar 2008 Riding Crew

  18. #18
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    Quote Originally Posted by Raptordude
    Good idea. DHX's are dope as hell.

    Fox has good turnaround too.
    I'll tell you this much.... I called Fox this morning, wait time was less than one minute on the phone. The rep who picked up was extremely helpfull and nice. He explained to me what he thought the issue was, told me not to worry that he will take care of me. Within 5 minutes he set me up an account, gave me an RA number, the address to ship it to, and said right now they have a 4-5 day turn around once the shock get to them. Total time on the phone,.... 7 minutes. Great service! So far I am very impressed with Fox.

    Last time I called Zoke,... a total of 50 minutes on the phone and the rep told me I did something wrong to the 888 when I changed the oil so they might not warranty it. I told them I changed the oil as soon as I got the fork because it did not feel right. Opened it up, there was no oil in one leg and less than 50cc's in the other. Zoke seemed to try to pull excuses to why the fork was acting the way it was, and basicially blaming me. I did end up sending my 888 in, took 3 weeks to get it back. Once I get it back and on the bike,... there was no change in the fork from when I sent it in. It still clunked, felt sloppy, and was sticky in the first 30mm of travel.

    I can only hope the experience so for with Fox will be the same throughout the process of getting this DHX fixed up.
    "We can always find excuses if we want to find them, but if we really want to do something, we have to just go."

  19. #19
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    mine made a similar sound like that for one day. let all the air out and fill the air chamber back up again, thats what i did and that seemed to work for some reason

  20. #20
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    can i ask what he thought your problem was out of curiosity?

  21. #21
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    Quote Originally Posted by bustanutley
    can i ask what he thought your problem was out of curiosity?
    The rep said that somehow I must have rode the shock with less than 125psi in the boost valve. I told him I put 150psi in there and rode it. He said the sound was most likely from oil getting behind the IFP (internal floating piston). He said this WILL happen if it is ridden with less than 125psi in the boost valve. And the noise was the oil being squeezed by the IFP. So most likely there is a leak in the valving which let air leak out, resulting in less than 125psi in the boost valve. When i rode the bike next it must have caused the problem. I guess... I am going to call back when I get the reciept for the shock from my LBS to clarify the info. I don't know for sure though, I know nothing about how shocks actually work and all the shizzle inside them. I hope this made sense.
    "We can always find excuses if we want to find them, but if we really want to do something, we have to just go."

  22. #22
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    yep, makes sense, that is what I thought may happen

  23. #23
    No Fear
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    Besides bleeding it. Change all O-rings .Specially the one round the IFP.

    Also check your damper nut for loosening. A small nut which keeps the washers and springs over the orifices At the end of the shaft .

    And another issue could be your teflon wear. A green seal round your damper it could bypass fluid.

  24. #24
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    my shock makes that sound, it's pretty damn loud, it feels fine thou so I'm not going to worry about it right now.

  25. #25
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    well okay that may have worked for your shock but i had also lost the bottem 10mm of movment had NO rebund damperning and there isno sighns of oil leaks.
    Quote Originally Posted by [Orge
    ]
    This problem could quite simply be solved if people would stop buying Konas.

  26. #26
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    Mine starts doing that when i wind the damping down, with the correct (for me) air and damping it stops - heard it before on other peoples bikes too, never heard of it being a problem.
    i always assumed it was just caused by a combination of different settings rather than a problem, never had any issues with the performance of the shock.

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