Anyone know what would cause fork failure this severe?

Marty1028
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Marty1028
Edited Date/Time 9/6/2022 7:19am
Wrenching on a project bike I just bought, took the front wheel off and the left side inner fork tube dropped out of the upper tube. What would cause this? Complete failure/break of the bushings and/or the rebound damper?

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ML512
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ML512 9/5/2022 4:56pm
9/5/2022 4:56pm
Wow that fork has a pretty long inner tube...

Could be as simple as the damping rod coming unbolted from the rebound bolt in the lug. Or the rod could've stripped/failed in some way.
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Marty1028
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Marty1028 9/5/2022 5:00pm
9/5/2022 5:00pm
ML512 wrote:
Wow that fork has a pretty long inner tube... Could be as simple as the damping rod coming unbolted from the rebound bolt in the lug...
Wow that fork has a pretty long inner tube...

Could be as simple as the damping rod coming unbolted from the rebound bolt in the lug. Or the rod could've stripped/failed in some way.
I’m going to disassemble the other fork to see if they’re the same length. It seems that the inner tube tapers in halfway up the fork. I have no idea if thats factory or someone’s really jank repair.
Bennett59
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Bennett59 9/5/2022 5:17pm
9/5/2022 5:17pm
My 2016 did this, the suspension guy just told me something broke inside didn’t really say much more. I felt like the bike was pulling harder to one side and I the air felt like a weird drop out feeling. Took front tire off and mine looked like that.
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Layton
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Layton 9/5/2022 8:08pm
9/5/2022 8:08pm
Not bushings. Most likely the rebound rod came loose.
Skerby
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Skerby 9/5/2022 9:54pm
9/5/2022 9:54pm
I had the rebound rod come apart up in the cartridge before. 2011 250sx
user760a
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user760a 9/6/2022 7:06am
9/6/2022 7:06am
If this is a mystery to you, I am going to go out on a limb and guess you don't often disassemble forks to change seals, etc.
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bvm111
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bvm111 9/6/2022 7:12am
9/6/2022 7:12am
no attention to detail upon reassembly is my guess… scared to think what it looks like inside.
Jbulz
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Jbulz 9/6/2022 7:15am
9/6/2022 7:15am
I would bet whoever serviced the fork last left the damper rod jam nut loose (the silver part shown at the bottom of #4). That's a scary failure mode!
mxking6
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mxking6 9/6/2022 7:19am
9/6/2022 7:19am
Jbulz wrote:
I would bet whoever serviced the fork last left the damper rod jam nut loose (the silver part shown at the bottom of #4). That's a...
I would bet whoever serviced the fork last left the damper rod jam nut loose (the silver part shown at the bottom of #4). That's a scary failure mode!
Yep. That’s exactly the problem
Not-a-Fan
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Not-a-Fan 9/6/2022 10:01am
9/6/2022 10:01am
I would not ride that without checking the other side. Super quick check. Will take longer to remove/install the fork from the clamps. Plus will give you some peace of mind. There was a video I see on IG or something where someone's forks completely came apart on a jump and the dude went over the bars at speed and scorpioned so bad it was almost unwatchable. Almost.
honda65
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honda65 9/6/2022 12:49pm
9/6/2022 12:49pm
This looks like a WP fork. They had a nasty habit of the cartridge unscrewing. The old closed chambers did this on occasion and the 4CS did it all the time. I kept a log of every set of 4CS that came through my shop that were already loose, or on their way there. I've seen them with 2 hours, others start at 40hrs. I had over 70 fork sets that had an issue

100% human error....not enough or no thread-lock.

Interesting thing.....This only was in the KTM fork versions, I never had one Husky 4CS have a problem.

I have heard KYBs can come unscrewed as well.

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