RS Reba Dual Air loses travel at 50% negative pressure?

[Rebbit_Cro]

Hi,

Few months ago i bought 2009/2010(not sure) RS Reba SL Dual Air 100mm. Seller says it is OEM fork (specialized).
I gave to guy who just had to remove 20mm spacer so i can have 120mm Reba (ATC issues). But, unfortunately, it doesn't work. works excellent on 100mm, but when it is on 120mm i have issues mentioned below:
So, if you pump positive chamber (let say 80PSI) the stanchions go out for about 125mm, but when you pump negative chamber (to35-40PSI) it is all good, but if you pump negative over 40PSI (so, more than 50% of + chamber), the fork sucks up the stanchions for about 2cm (or if it doesn't, when I touch the handlebar fork just drops for 2cm). If you pump even more, up to 80/80. the fork will be max 95mm of travel, and it will work like sh...t..
It was reasembled 2-3 times after the issue found but nothing helped, then returned to 100m and works like a charm...

Did someone find out what could cause this issues?

Regards.

 

[sharky]

sound´s like "the guy" re-assembled the fork in a wrong way. if he put a distance spacer into the negative chamber the chamber is to big and the effect as you describe occurs. having a Picture of your DA unit would help to clarify that

 

[Rebbit_Cro]

"the guy" also took the fork to the other guy who also services forks for several years, and nothing.

He couldn't put distance spacer in wrong position because 120mm doesn't need any spacers. But he also tried later with putting spacers belowe and above the negative piston... just to check..

or, at least he told me that...

I think ill go buy some tools to do it by myself.. and also try to see whats the cause of it...

Ideas are welcome

 

[sharky]

if you know that well how the DA unit Looks like I ask myself why you´re asking us

there´s more than the reavel spacer in the DA unit and "the guy" definitely can assemble the remaining parts into a wrong order

 

[Rebbit_Cro]

you're right
i don't know exactly how it looks like.. i assumed as i know how my revelation looks like

when i get the picture of it, ill post it and then take it from there.

cheers

 

[Rebbit_Cro]

HI, few weeks i posted this question..
today i got oportunity to disasemble the fork a take pictures..

this is the order of parts in my airshaft..
what do i need to do to extend to 120mm, only remove spacer and thats it or?

here is the pic - http://i.imgur.com/lc1ycXl.jpg

 

[sharky]

picture cannot be displayed...

 

[Rebbit_Cro]

I removed 20mm spacer and put everything back in same order.
Cleaned everything, put military grease everywhere, put 5ml oil in each leg and it works good.

No pressure loss, no travel loss. nothing... keeps pressure in both chambers as is..

 

[sharky]

the golden Support ring which is on your Picture left of the 20mm travel spacer Needs to be placed over the crush washer when you re-assemble the DA unit. that´s the only Thing looking incorrect that I can see at the Moment

 

[Rebbit_Cro]

I have put all back in this order as it was in the manual - so, support washer over the wavy washer.