Rockshox dual air problems

[Guest Smimby]

Does anyone know what pumping the neg chamber will cause the fork to become "shorter" and releasing the air causes it to go back to it 100mm

 

Not enough pressure in the pos Chamber? But I checked it and all looks good, it is maybe that the air is leaking past the o-ring?

[Captain Fastbastard Mayhem]

If the neg pressure exceeds the pos pressure, it pulls the fork down into its travel. Normal for a dual air fork for that to happen. To remedy it, take out all the neg air, set sag on positive air pressure only and then pump up neg air to 0-5 psi below the pos air pressure.

[Guest Smimby]

I did that but it keep sagging....after a short ride...you think that pos is leaking air hence loosing pressure and then the neg pulls it down?

[Captain Fastbastard Mayhem]

I did that but it keep sagging....after a short ride...you think that pos is leaking air hence loosing pressure and then the neg pulls it down?

 

yeah, possibly...

[TNOSE_E]

Sound like an O-ring has failed or turned on the air sprung side.

[Skinnyone]

It needs a service as the air is transferring between the chambers due to a worn O-Ring...

[Guest Smimby]

It needs a service as the air is transferring between the chambers due to a worn O-Ring...

But which O-Ring the Pos or Neg piston one?

[Skinnyone]

There is only one, send it in to Cape Cycles for a full service and they will do a full rebuild and replace all the o-rings and seals one hit...Their service centre up in gauteng charges about R800...

[Guest Smimby]

There is only one, send it in to Cape Cycles for a full service and they will do a full rebuild and replace all the o-rings and seals one hit...Their service centre up in gauteng charges about R800...

Thanks, but according to the documents there are 3 O-Rings...hence the question

[Skinnyone]

Ah ok well its been a while since I last opened one, I apologize, its better just to replace all of them anyway then there can be no mistaking...

[Guest Smimby]

Ah ok well its been a while since I last opened one, I apologize, its better just to replace all of them anyway then there can be no mistaking...

 

[Captain Fastbastard Mayhem]

Take it to Stoke

[David Marshall]

There are three o-rings. Two on the -ve piston, the one between the piston and stanchion is 3.5mm by 21mm (not easy to come by so use a 3.5 by 20mm) the other between the piston and the shaft is 3mm by 10mm. The positive piston has one, also 3.5 by 21mm. Lube the o-rings and the lowers as per U tube. You will probably need crush washers on the lower nuts as well. I am sure that the guys at Stoke can supply you with a "kit" or do it for you.

 

When pumping I usually pump the negative first to about half the pressure that I want the positive to be, then pump the positive. Go back to the negative and adjust if necessary.

[Skylark]

Major service on that fork incl changing all the orings is soooo easy! Orings at the bearing shop(some are imperial) and crush washers are normally still good to go if still fresh from a previous service, I've reused mine 3 times now and still all peachy, next service they need replacing though.

Let out the air from both pos and neg, set sag to your weight by pumping the positive side only and then pump the neg just until you see the first signs of the fork travel dropping, I normally put the O-ring 1mm above the fork seal and once that hits the seal I stop pumping the neg.

Edited August 22, 2014 by Skylark