Sucking (vacuum) sound from my FOX fork

[tonyride]

I have a Fox 36 Float Factory fork with Kashima (circa 2016) on my Pivot Mach 6. The fork feels and performs great and I really have no issues with it functionally. The only "issue" I have with it is that it makes a sucking or vacuum kind of sound when it hits bumps. I'm not sure if the sound happens during compression or rebound or both but it is definitely noticeable. It even comes through on videos taken with my GoPro. It's been doing that since day 1 and I never really gave it a second thought but I'm just wondering if this is normal or if that's something I should address before I take it out to Moab in a couple of months. I've had several other Fox forks and all of them were dead silent.

You can hear it in this video as soon as I get in the woods and consistently for the next minute and a half:

thanks.

 

[Glenn Rides After 4 PM CST]

Mine does the same. I think it's rebound related. Try adjust the red rebound knob under the cap. Right lower fork leg.

 

[tonyride]

Mine does the same. I think it's rebound related. Try adjust the red rebound knob under the cap. Right lower fork leg.

Thanks. I'll give it a shot.

 

[68nova200]

I haven't ridden a fox fork yet that doesn't do this... I'm pretty sure its there to scare off bears.

 

[sundaydoug]

That doesn't sound normal, none of the Fox forks I've ridden sound like that. The rebound knob should be used to adjust rebound damping levels, not to tune out an unwanted sound. Get a full service done on it then see if the sound persists.

 

[Dingo]

My 2017 34 has done it since new. Fiddling with rebound changes the sound.

Set the rebound where you like it, not for the sound of it.

 

[bergsnj]

its not unusual. i would suggest if you have never had a lower end service on the fork to do that sooner than later. That might quiet it down.

 

[MadisonDan]

 

[stb222]

It is the rebound, your shock should be making the same sound. It has nothing to do with service.

 

[Karate Monkey]

Oil passing through the damper ports. In an extreme case, it could be cavitation, but the damping would be almost non-existent if that was the case.

 

[pooriggy]

Give me your fork(fork it over), buy a new one.

 

[cbiker]

Its normal its the oil passing through the damper if it wasnt making that sound then you woulf have little to no dampening. You could reduce the damping the sound should go away but then your fork will be like a pogo stick

 

[tonyride]

Thanks for the assuring responses you guys. The fork feels fine and like I said, it was making that sound from day one and I got the bike brand new. I'll try messing with the rebound a bit and see how that goes. I wouldn't want to sacrifice rebound too much just to quiet it down so if the sounds goes away without reducing the ride quality then great. If not then I'll just live with the sound. Scaring the bears is a bonus. Thanks again.