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Discussion Starter · #1 ·
I just mounted these on my bike and they will now not extend past 110mm. Out of the box, I compressed them and they returned to full extension. I heard what sounded like air passing a seal, but didn't think much of it as I knew they weren't pumped up. I mounted them, pumped them up to 105 (they came from factory at 50), put the suggested 7 clicks and took it for a ride. Initially, they were fine, but slowly started to compress. After my ride yesterday when I noticed this, I could pull the fork up about 20mm but it would pull right back. I bled all of the air out thinking it might act as a " re-set" and as I did, the forks slowly collapsed as the air was let go. I pumped them up again, this time to 140 and they began to extend but would not extend past 110mm. What is the fix?
 

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This is a symptom typical of air trapped in your negative chamber. I would start by slowly letting out all the air to allow it equalize. Then reinflate it while cycling the fork every 20psi or so.

I’ll let the suspension experts chime in but if that doesn’t do it you will likely have to service your air shaft. Sadly forks often come from the factory with incorrect levels of grease and oil.
 

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I have a Fox fork but this could still be applicable. Deinflate the fork and manually extend and compress it several time with the pump still attached and releasing pressure. Pump it back up 25psi at a time until you reach your desired pressure. Each time cycle the fork slowly many times at least 25% of it's travel. Your problem could be a pressure imbalance between the positive and negative air spring that is preventing the fork from getting full travel. Cycling the fork as you inflate will balance the chambers as there is a point in the stroke where there is a dimple or something that allows air between the 2 chambers. Too much pressure in the negative spring will push the fork down. The air passing a seal could be the noise of the chambers slowly balancing out.
 

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Discussion Starter · #4 ·
Thanks guys. I just found the "ATA" fix in the stickies, but it seemed that was for older models. I'll try your fix, and wait if anyone has any other info. Really disappointing to have this happen on a brand new item.
 

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Is this a Z1 or or Z2? What travel is it supposed to be?

It’s probably one of two things - the fork was set to a high pressure at some point then the air let out to fast so it blows past the equalisation point. Pump it up to the max pressure and try pull it out as far as you can. When it reaches the dimple near top out it should balance out the pressures again, then let the air out slowly and stop if if starts to sink and pull it back out.

If it still refuses to extend - it is possibly an assembly error - was the travel altered for you when purchased? Could be debris on the air piston that allows air to bypass, or someone put too much oil/grease and it’s filled up the negative chamber. So I would send it back to Fox and get them to fix it, then it’s highly unlikely to happen again
 

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Well, I take it back. I just returned get a ride and the forks are stuck down below 100mm. So the likely culprit is too much grease blocking the relief hole?
No grease can't block the hole, only fill up the negative space to the point where it is tough to reach toput. Either way it sounds like the fork needs to be opened up and fixed
 

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Discussion Starter · #11 ·
I have a Fox fork but this could still be applicable. Deinflate the fork and manually extend and compress it several time with the pump still attached and releasing pressure. Pump it back up 25psi at a time until you reach your desired pressure. Each time cycle the fork slowly many times at least 25% of it's travel. Your problem could be a pressure imbalance between the positive and negative air spring that is preventing the fork from getting full travel. Cycling the fork as you inflate will balance the chambers as there is a point in the stroke where there is a dimple or something that allows air between the 2 chambers. Too much pressure in the negative spring will push the fork down. The air passing a seal could be the noise of the chambers slowly balancing out.
I haven't ridden it hard yet, just up the hill to my house and back to my shop a few times, but it seems to have worked so far. I have cycled it manually many times too, and still extending fully. Don't know if I'm skiing tomorrow or riding, but I'll update after I do.
 
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