Fox DPX2 top out kn...
 

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[Closed] Fox DPX2 top out knock

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I have a transition sentinel which has a dpx2 shock. It feels like there is some knocking from somewhere on small chattery bumps.

It’s not very old and all bearings and bushings are tight.

Rebound is slowish, compression fully open.

It either feels like a top out clunk, or like there is an air gap or something.

I have set it up as per instructions, ie slowly and regularly cycling it to get the air equalised and used a shockwhizz which identified that it was all working ok.

Any thoughts?


 
Posted : 23/10/2020 9:18 am
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Can you feel the detents when you turn the rebound knob in both directions?


 
Posted : 23/10/2020 9:19 am
 5lab
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I had an old fox shock that did this - the nut holding the shimstack was coming loose, so every time it moved from compression stroke to rebound stroke, or visa versa, there was a knock as the shims moved up and bashed against the other end


 
Posted : 23/10/2020 9:26 am
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I have a rattle from my dpx2,
5lab is the nut DIY fixable?


 
Posted : 23/10/2020 12:01 pm
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But will need a damper strip down, so not a home job unless you’re proper keen (and have the ability to recharge the shock). If it is that (I’ve had it happen on a couple of shocks I’ve the years) it can be possible for the entire shock to split in two (on a coil at the least).

Are you also getting the noise when the shock goes from compression to rebound? As the shim stack will also be moving around at that point if it’s loose


 
Posted : 23/10/2020 12:53 pm
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Mmmmm. Need to have a ride and check. It’s not that old <6 months.


 
Posted : 23/10/2020 11:42 pm
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If its less than 6 months old and knocking send it to Silverfish for warranty. (if you have proof of purchase)

DPX2 service manual

https://www.ridefox.com/fox17/help.php?m=bike&id=890


 
Posted : 24/10/2020 12:58 am
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I warrantied a DPS evol for a similar problem - a knock about a third of the way through travel. Also had the spinny rebound knob, so I suspect it needed IFP recharge etc.

Was a pretty quick process. However, the spinny knob is now returning...and it's out of warranty now.


 
Posted : 24/10/2020 1:03 pm
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Sent it back to silverfish. Had a play around with it in the garage to try and replicate it. It appears to be a definite knock when I quickly compress it and then it returns, tried all extremes of compression and no difference.

Also slowly deflated it and then back up, cycling it every 50 psi and it’s still there.

Will see what they say.


 
Posted : 27/10/2020 9:08 am
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I’ve booked mine in for a warranty.


 
Posted : 27/10/2020 9:29 am
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So I have the shock back, no issues found but still there appears to be something amiss. I tried totally winding off the rebound and it appears to go away. Is it possible the shock is packing down?


 
Posted : 30/10/2020 7:42 pm
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Hang on....my shock pump dial may be completely screwed! Let me try with a different pump. Might have too low pressure.


 
Posted : 30/10/2020 8:29 pm
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So. Used the shockwhiz again, much more pressure than before but also wound out the rebound so it was much faster. Been for a ride and the knocking has gone. Appears it was packing down too much. Perhaps.


 
Posted : 01/11/2020 7:50 pm
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3ride old dpx2 on a sentinel here and same knocking noise over chattery bumps as you describe. Rebound knob makes no difference to the shock it’s either fast fast or fast.
Warranty inbound. Hoping for a quick turnaround and a quiet bike!!


 
Posted : 01/03/2021 5:40 pm

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