Cavitation

lugsey2k5

Hello
I suspect my rear shock a fox rp2 has cavitated. What are the consequences of this?
I assume a mojo service is required to fix this.
Thanks for any help

supersonic

Why do you suspect that? What are the symptoms?

The damper is unservicable at home without nitrogen charging equipment - never attempt to open the damper.

lugsey2k5

squelches on compression from cold. it was MOJO suggested it was cavitated.

supersonic

Many shocks squelch as the oil is forced through the valves.

Cavitation is air in the system, or reduced nitrogen pressure which causes bubbles in the damping fluid. This can cause a loss of damping performance - is this happening?

I'd probably speak to MOJO again and ask them to explain.

nicklouse

if it feels the same dont worry.

lugsey2k5

I will have a proper feel the next time im out. Can it cause any damage?

Thanks for the help/ quick replys

supersonic

It can create a mini wormhole that will suck the innards out of your shock and transport them to another dimension.

Apart from that, things should be fine

The Northern Monkey

supersonic wrote:

It can create a mini wormhole that will suck the innards out of your shock and transport them to another dimension.

Apart from that, things should be fine

Sweeeeeeettt

Did Brian Cox tell you that?

cavegiant

A simple way to check if it is BADLY cavitated.

Set the rebound to be slow as possible.
Fully compress the shock and let it sit for a few seconds.

then let go.

The shock should take a few seconds to slide smoothly back up.

If cavitated it will either shoot straight back (so no real rebound damp) or will slide slowly, and then when it runs out of oil, will shoot up.

Either way this is a win win situation.

Send it to Mojo and ask for them to custom tune it while it is open.
Then if cavitated or not, you get the custom tune for £30 without having to pay a service charge =-)

Custom tuning is a huge improvement on a shock.

lugsey2k5

thanks nick and sonic.
Cavegiant, is cavitation covered under the one year warranty?

kevolution

Technically, no. But it's an indicator of poor setup. So yo could try and get it done under warranty from the shop that set your shock up poorly when you bought the bike.

But you'd have to prove that you never made any adjustments to the shock since they set it up.
Not possible usually.
Send it in for the annual service at Mojo and they'll set it up correctly , and you get your 2nd year of warranty coverage.
The custom tune from Mojo is fantastic. They build speed sensitive stacks into the damper so it's virtualy automatic.
You just plug and play. The experts have taken care of all the complicated bits.

lugsey2k5

emailed mojo and they said its under warrenty:)
Is custom valving really worth it? im happy with the shock although i switch between PP and fully open a fair bit as fully open drops the seat hight a little too much for climes etc

cavegiant

The custom tuning is unbelievably worth it.

Best £30 investment on my bike ever.

p.s. I think warranty is 2 years, and cavitation is covered.

supersonic

Custom valving is good if you know what you want from the shock. Two identical riders may prefer totally different shock set ups on the same bike.

Speak closely with the tuners.

lugsey2k5

OK so played with the bike today and as usual the first half a dozen or so compressions cause a squelching sound then after that it pretty much goes.
I played with the rebound and when set to slowest it rebounds slowly at a linear rate as you would expect.

Think ill send it to mojo and if its not a cavitation problem, worst comes to worst i pay for a service.