Rockshox Pike airshaft sucked up into upper.

[Steady Spin]

Did my lowers service about two weeks ago and reassembled the fork while fully compressed which shouldn’t be a problem. 

Noticed post assembly that it was sucking down slightly into the travel. Burped the fork with the cable tie trick and it was fine. 

While prepping bikes on Friday night I noticed an oily rebound adjuster and realised I mist have gotten some oil into the damper shadt when filling it so I pull the fork apart to clean and change the oil again. 

Straight after letting the air out of the fork the airshaft sucked itself all the way to the top. 

No amount of pulling on the fork seems to clear out the equilisation port on the airshaft. 

Anything I may have missed or can try before taking it in? Sucking down about 5mm into the travel at the moment and does sound quite squishy when riding. 

[BaGearA]

Look down the threaded part on the shaft at the bottom , there might be a valve head depending on the model press it and the negative will empty (pressure in negative and no pressure in positive is sucking it down )

 

otherwise wrap a rag around the end of the shaft and release the c-clip (make sure your head is out of the way ) its going press out quickly and make a loud noise but won't fly out if you don't run a really high fork pressure.

[Steady Spin]

Thanks. It is a 2020 and I didn’t see a valve to release the pressure. 

One tool I need to get is a pair of c-clip pliers. I think I should leave this one to a shop to check. Also need new foam rings from the looks of it. This set is deforming a bit and didn’t come clean during the alcohol bath. 

[OVERDRIVE]

This here is a @Jewbacca topic 🏃🏾🏃🏾🏃🏾

[Jewbacca]

4 minutes ago, OVERDRIVE said:

This here is a @Jewbacca topic 🏃🏾🏃🏾🏃🏾

This is a Droo topic!

But in my very humble opinion you have to get the air out of the negative air chamber. 

Either by cycling through the travel adding tiny increments of psi then taking them away then adding again whily cycling through the travel OR pop the shaft loose without taking out one of your eyes.

I would be tempted to strip it, lay it out again and start again as opposed to try to 'fix' the fork dive in situ

[Steady Spin]

I’ve tried the hard tug on the fork while it has no air pressure to clear out the equilisation port but i get a loud’ish pop and squelch and it sucks down again. 

Haven’t tried the incremental filling method yet. 

@droowhat do you think?

[Alouette3]

Have you had the air shaft serviced yet?

I know on some Fox 36 forks they have too much grease in the air sleeve and this blocks the port, preventing proper equalising of pressure. I services a friend's 36 and even at operating pressures in the positive chamber it was sucked down almost 50mm!

Its fairly straightforward and Rockshox has great service manuals.

[Steady Spin]

14 minutes ago, Alouette3 said:

Have you had the air shaft serviced yet?

I know on some Fox 36 forks they have too much grease in the air sleeve and this blocks the port, preventing proper equalising of pressure. I services a friend's 36 and even at operating pressures in the positive chamber it was sucked down almost 50mm!

Its fairly straightforward and Rockshox has great service manuals.

Had a major service from Cogent in November 2021. 

[OVERDRIVE]

1 hour ago, Jewbacca said:

This is a Droo topic!

But in my very humble opinion you have to get the air out of the negative air chamber. 

Either by cycling through the travel adding tiny increments of psi then taking them away then adding again whily cycling through the travel OR pop the shaft loose without taking out one of your eyes.

I would be tempted to strip it, lay it out again and start again as opposed to try to 'fix' the fork dive in situ

This is why I pass it along to you. I just ride the thing! 

[Steady Spin]

Ill say this, this Pike has never had such amazing small bump performance. Smooth a butter. 

[droo]

A few things, but I'll start with your main problem - your air spring is stuck down. I'll provide solutions for all forks for when anyone else has this problem.

 

The first thing to try on any fork that self equalises (RS Solo Air, Fox NA2, Ohlins, Marzo 2018+), inflate to max pressure, then extend the fork by pulling up on the crown and down on the wheel or the arch. You should hear a hiss as the air passes through the transfer port from the negative chamber into the positive.

 

If this doesn't work, first let all the air out of the positive chamber, then:

 

On older 32mm RS forks there's a valve at the bottom, both on the dual air and solo air variants. Solo air you have to remove the spring side footnut to get to it. Depress valve, air comes out. Job done.

 

On the older 35mm RS forks, the air spring shaft is shorter than the stanchion tube, so when the air is released from the positive chamber and lowers are off the spring sucks into the stanchion past the seal and it the air escapes. Easy enough.

 

On the newer air springs is where it gets fun. There's no way of letting the air out of the negative spring, so you've just got to take the circlip off and pull. Loud and messy, but because the lower seal head is held in place by the footnut there's no resultant force to make the spring or seal head fly out. As soon as you break the seal between the stanchion and the seal head, the air escapes and you're good. It'll most likely have a whole lot of oil and grease in it as well, so cover the end with a rag before you remove the circlip and dislodge it or you'll be cleaning grease out of your teeth, hair and facial orifices for a few hours afterwards.

 

Warnings: don't look directly down a pressurised tube (it'll be tempting when you're removing the circlip, but don't do it). Don't stand directly in the line of fire when disassembling. Ideally, safety glasses are recommended. And if any of this makes you uncomfortable or you're the type to call your lawyer if it goes pear shaped, take it to a professional. 

[droo]

As for the rest:

 

Don't stick zip ties down your fork seals, for the love of Jehovah. If you have to release pressure from lower legs (unlikely unless you've climbed 3000m in a day), do it via the footnut holes.

 

If your foam rings are dirty, replace your wiper seals. Foam rings there to catch the crap that gets in when the seals can't. When they're dirty, the seals are done. Cleaning them with alcohol will swell them and render them useless.

[Steady Spin]

Good to know. Thank you. 

Can they we worn out from about 6 months of use? Was replaced in November and they still look perfect.

Noted on the burping with cable ties and use of alcohol. 

[droo]

Depends how much you ride. 150 hours and you're done, and that can come up quicker than you think. Worn seals and new seals look the same, except for the grubby foam rings under them, which is one of the reasons foam rings exist.

[Steady Spin]

Calculated at around 100 hours but dropped it off for a full service now. 

Better safe than sorry. Fraction of the cost of a new fork. 

[droo]

And Jacques can deal with the high velocity release of oil. Also much safer.