WP AER Forks Collapsed after Rebuild then Extended Back to Normal

Vonripper450
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Vonripper450
My friend rebuilt his AER forks and everything appeared to be good to go until he tied the bike down for a while. The forks eventually collapsed but, after putting the bike on the stand for a while, the forks extended and have 150# pressure on them which is the pressure they started at. He rode around the yard after they re-extended and checked, no pressure lost. Is it possible the seal between the positive and negative chamber leaked a bit then sealed? Would you tear it down or try to run it. Thanks guys for your help! It is much appreciated.
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Rickyisms
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Rickyisms 8/14/2022 1:32pm
8/14/2022 1:32pm
I would tear it down. Something about them collapsing on the face of a jump seems pretty terrifying.
MX558
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MX558 8/14/2022 3:10pm
8/14/2022 3:10pm
That happened to me but not after rebuild . It was the second issue with air forks with KTM . I went KYB conversion and couldn't be happier
Bruce372
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Bruce372 8/14/2022 5:12pm
8/14/2022 5:12pm
If they are functioning correctly after a quick ride, you should be fine. After rebuild of the air piston seal, they can act a little strange from grease filling the air bypass slot. At least, I experienced this.

They are reliable forks, and easy to service but easy to service wrong also, but just make sure it's been done properly and is safe to ride. There are special tools from ktm to rebuild both piston and cartridge seals, but there are work arounds also if you know what you are doing.
Broseph
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Broseph 8/14/2022 6:49pm
8/14/2022 6:49pm
Vonripper450 wrote:
My friend rebuilt his AER forks and everything appeared to be good to go until he tied the bike down for a while. The forks eventually...
My friend rebuilt his AER forks and everything appeared to be good to go until he tied the bike down for a while. The forks eventually collapsed but, after putting the bike on the stand for a while, the forks extended and have 150# pressure on them which is the pressure they started at. He rode around the yard after they re-extended and checked, no pressure lost. Is it possible the seal between the positive and negative chamber leaked a bit then sealed? Would you tear it down or try to run it. Thanks guys for your help! It is much appreciated.
Sounds like the piston is slowly leaking air. After being tied down for a while, air leaked past and equalized pressure on each side.

Not really a big deal, the forks are made to leak air around the piston and equalize right before they top out. So as long as the leak stays slow, it will be corrected each time the forks extend. Probably won’t even notice it in normal use.
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