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Discussion Starter · #1 · (Edited)
I recently had GP cartridges installed and am experiencing a metallic thud when the fork is fully extended (ie: rebounding from wheelies, going over railroad tracks and large potholes, etc.). When I put the front on a triple tree stand, I can push the fork(tire) down and hear the sound. It's definitely coming from the forks, not the brakes or head bearing, etc.

Does anyone have any ideas as to what may be happening?

It sounds/feels like I'm missing a bumper bushing, (if they even have them). Low oil? I'm waiting to hear back from the installer but wanted to get some other opinions. The bike rides great except when the forks get fully extended. BTW, I haven't measured sag yet since I assumed the cartridges would be "in the ballpark" upon arriving. Thanks in advance for your input.
 

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Discussion Starter · #4 · (Edited)
Do you know how much oil was put into each leg?
I'm not sure how much oil they put in each leg. I just took took the fender and calipers off along with double checking the steering head for looseness. I was able to isolate the sound to the left fork leg. I can pull it down and it makes a metal on metal sound. The right leg give resistance when I pull down. I'm starting to feel that it's an oil level issue.
 

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Discussion Starter · #8 ·
Here is a video of the noise the left leg is making. It's definitely more pronounced with the addition of the front wheel and momentum.

 

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Man, sounds like I'm not allow with the bad fork cartridge syndrome. Both my leakie cartridges arrived back at the installer today. Waiting to hear what is wrong. Good luck on locating your issue.
 

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Delnari has another thread about getting his cartridges back from a "Professional" installer with massively leaky seals. Sounds like the goofball "Professional" probably picked them up by the upper tube and jammed them back together when they came apart.
 

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Delnari has another thread about getting his cartridges back from a "Professional" installer with massively leaky seals. Sounds like the goofball "Professional" probably picked them up by the upper tube and jammed them back together when they came apart.
More than likely caused by dirt. There is no need to remove the outer (gold) tube during cartridge work. Similarly, just picking up on the gold tube won't separate it from the slider.

Fork work requires obsessively clean tools, work area, and procedure.
 

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I have done 100 sets of motocross forks, and have never ever ruptured a set of seals just pulling the cartridges out. Like you said, the tubes don't need to be seperated, but somehow the technician ruptured both of them doing a cartridge replacement, thus my comment. I have never tried to separate tubes that weren't in a vice, without pulling the dust seal, clip, and yanking them apart.
 

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I have done 100 sets of motocross forks, and have never ever ruptured a set of seals just pulling the cartridges out. Like you said, the tubes don't need to be seperated, but somehow the technician ruptured both of them doing a cartridge replacement, thus my comment. I have never tried to separate tubes that weren't in a vice, without pulling the dust seal, clip, and yanking them apart.
Agreed. If both seals were leaking, there is a good chance the tech was unsure of the task at hand.
 

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Discussion Starter · #16 ·
So I heard back from the installer and was told to send them back for so that they could inspect them firsthand. They seem to think the noise is coming from the spacer. They also said that they've heard a few of these cartridge kits make noise although they're not 100% why this happens to some and not others. Apparently the technician wants to try a spacer made from a different material, which will hopefully reduce the noise of impact when rebounding.


Here is a video of the noise the left leg is making. It's definitely more pronounced with the addition of the front wheel and momentum.

 

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That does sound bad.
The stock ones have some kind of oil damping method at the end of the stroke, even in the left leg. Sounds like your cartidges don't have that.
Is there any oil in them??? Is there any damping at all, can you hear oil being circulated???
 

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Discussion Starter · #18 ·
Definitely oil in them but not sure why only one sounds bad. The tech seemed to believe that the noise was coming from the spacer material which still doesn't explain why only one leg is impacting at the top of the stroke.


That does sound bad.
The stock ones have some kind of oil damping method at the end of the stroke, even in the left leg. Sounds like your cartidges don't have that.
Is there any oil in them??? Is there any damping at all, can you hear oil being circulated???
 
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