My pikes have started sucking down into their travel, they currently sit at 15-20% sag with no weight on the bike.

Had a search and found threads mentioning cleaning out the port between positive and negative air chambers.

I took the lowers off and noticed the air spring is sucked into the uppers. In all the videos I’ve seen the air spring gets pushed in by hand while removing the circlip.
I removed the circlip and managed to get the air spring out, but there was a pop as air released (stuck in the negative chamber I guess?).

I gave everything a clean and put it back together. Pumped back up and got all my travel back, forks feeling plush again.

This only lasted for 5 mins before sucking back down into it’s travel.

Had another search and found a few posts about a hidden schrader valve somewhere in the air spring that may be blocked / faulty. Is it worth trying out a new air spring, or should I just send them off for a service?

If they’re less than two years old send them back.

Doesnt sound like the typical vacuum in the lowers (mostly caused by MBRs youtube vid) as they were fine for the first five minutes.

Sound like an in balance between + and – chambers, if there’s more pressure in the negative than positive they will be sucked down, if transfer port clear then + chamber loosing air?

I’m the second owner so can’t return under warranty unfortunately.

Yeah they felt good for a short while so think it is an inbalance in the chambers. If the port is clean is it likely to be a problem with the air shaft itself?

Scratched air tube? There’s only a seal on the piston head to be at fault apart from that.

Or go coil.

I couldn’t see any scratches to the air shaft or tube in the stanchion.

They are due a service so think I’ll send them off and see what they say.

normally a blocked transfer port between the +/- chamber. a mates used to do this a lot, a sharp tug to pull them back to full length always cleared it with a pop/squelch sound.
alternatively, a lower service along with a clean of the air spring will sort it. dead easy to do.

Scratched air tube

Could be this, or something else wrong with the air spring. Its a very common fault with Rock Shox solo air forks. I went through two sets of Rebas under warranty with a similar problem.

From memory a new air spring isn’t that expensive (£30ish?) so perhaps get them to check and change during the service.

normally a blocked transfer port between the +/- chamber. a mates used to do this a lot, a sharp tug to

this

fit a luftkappe!

I’ve tried pulling up but doesn’t seem to want to budge, cleaning port didn’t make a difference either.

devash – sounds like a plan

It will either be a scratch in the stanchion or it might just needs a new quad ring on the air piston. Was the grease on the air piston black in colour. Drop me a message if you want me to send you a new quad ring.

Cable tie under the seal untl you hear a psssst sound.

You’ve got the extra negative spring thing going on.

this happened to my pike a few months ago. turned out to be a scratch on the stanchion. ended up getting it converted to coil by TF tuned. now it feels better than it ever has!

Sent mine to TF for annual service they noticed a warranty issue and all I needed to do was send them my invoice. Got a brand new set a week later. They did the rest.

Servicing pays, top service.

Cable tie under the seal untl you hear a psssst sound.

You’ve got the extra negative spring thing going on.

Doubt it as it was fine for the first 5 minutes, if either the + or – were leaking into the lowers that would create pressure not vaccum.

Had the exact same problem with mine recently. Took them apart, cleaned them (including the transfer port), noticed no damage, put them back together and they worked fine for the first descent and then back to sucking down about 15-20mm into the travel. I sent them to TF Tuned and they inspected them and found a chip in the air shaft (which I didn’t find)… now I’m waiting for a coil conversion 🙂

I sent them to TF Tuned and they inspected them and found a chip in the air shaft (which I didn’t find)…

I reckon its a fair assumption the + was leaking air out/or into the -, cant think of any other way they would suck down apart from vacuum in lowers.

Bravesirrobin

Exact same.
£30 or so for new air shaft plus cost of a service.
Fine ever since.

(Reba’s in my case)

It’s most probably a leak between positive and negative air chambers. As the fork compresses, positive pressure rises and if the seal isn’t good, some air leaks to negative and stays there, sucking the travel down.
First thing to do is service them and replace the internal seals. It’s an easy job to DIY but you’ll need a full seal kit. If that doesn’t cure it it’ll be a scratch on the inside of the chamber or on the air shaft itself. If it’s a cartridge (I don’t know how old the fork is or exactly how the most modern stuff is constructed) you can replace it, or if you’re lucky it’s the air shaft that’s scratched. If not, and it’s a scratch on the inner stanchion, you’ll need a new CSU, which ain’t gonna be cheap.
I’ve seen this more than once…..

A coil from CRConception is around half the price of a CSU….

Cheers for the advice.

I’ve booked them in with J-tech for next week. Would have a go myself but want to get back out riding asap.

Just to revive this thread, the sharp tug just fixed mine.

Sharp tug doesn’t really do it justice thou, I put the maxel back in without the wheel, stood on that and literally gave it everything I got.

With a massive resounding POP out they slid, awesome work dudes.

Let see how long it lasts…..

L

9 times out of 10 it’s due to an imbalance in the +ve adn -ve chamber pressure…

You CAN give it a yank, or you can just pump up the +ve pressure (i.e simply pump up the fork) until +ve > -ve, and then the fork will extend, chambers equalize, THEN you can slowly let out air to get back to your set pressure…

DrP

I tried that, but got the heebie jeebies @ 150psi, not sure if someone tried to service these before I owned them but there is a fair amount of grease down there when I took the top cap off. I very carefully cleaned up the obvious bits.

I think a proper service is on the cards

Cheers

L