PAR removal on 08 66 ATAs

RangaRMX

Likes Dirt
Hey guys, just contemplating taking out my PAR piston myself, was just after any suggestions to whether or not this is a good idea.

It's starting to really shit me that I cannot get full travel out of my forks, and although I've just accepted that my 66s were shit, I've recently read some glowing reviews of them after the PAR piston has been removed.

I'm just wondering if anyone else on here has done it themselves, or even had it done for them, and if so how difficult was it, what potential for error is there (I'm quite mechanically minded)? Also, I'm only going off what I read here..http://forums.mtbr.com/showpost.php?p=3195344&postcount=350..this is for the 07 forks, I'm assuming the only difference is that, by the sounds of it, the PAR chamber is on the opposite side to the 08 models..again I'm unsure of this however.

If at the end of the day it's gonna be a hassle or I might break shit then I'll just get them to take it out when they service them next, that's if they will do that for me..

So anyone with some feedback about this procedure, it would be great to hear your opinions on this process and the results obtained, stupid me only just found out there is a valve under the ATA cap too (cheers for the great instructions Marzocchi!!:rolleyes::rolleyes:), which alleviated my problems a tad, but still is bugging me not getting those other 2 inches!!! I was telling myself I was never gonna buy another one of their products again and stick with RS, but if this yields good results then I might stick with the 'Zokes...for a while...
 

AngoXC

Wheel size expert
Have a play around with this illusive valve you have just found...I do not deny that the ATA system is flawed, but if this one valve is making a difference, it might be comming back to simply the fork's set up.

Also check that the 2008 fork actually has a PAR chamber. I thought that for 2008, the 66 featured ATA-II which eliminated the PAR design...:confused:

If it is the same as the '08, I think the only real cause for trauma is setting your negative volume as it will greatly depend on not only your personal preference, but physical things like weights etc.

My $0.02
 

mr636

Likes Bikes and Dirt
removed mine on my 888 Wcs- big difference.
only thing you have to accept is the lack of any high speed compression control.
you will end up mucking around with the air pressure for a while, and then ytoull be sweet.
i had mine done by the LBS who new Marz stuff inside out.
 

zaccyboy

Likes Bikes and Dirt
removed mine on my 888 Wcs- big difference.
only thing you have to accept is the lack of any high speed compression control.
you will end up mucking around with the air pressure for a while, and then ytoull be sweet.
i had mine done by the LBS who new Marz stuff inside out.
What LBS would that be.
I am thinking of getting the PAR takin out of mine too. (2007 66 sl1 ATA)
 

RangaRMX

Likes Dirt
Have a play around with this illusive valve you have just found...I do not deny that the ATA system is flawed, but if this one valve is making a difference, it might be comming back to simply the fork's set up.

Also check that the 2008 fork actually has a PAR chamber. I thought that for 2008, the 66 featured ATA-II which eliminated the PAR design...:confused:

If it is the same as the '08, I think the only real cause for trauma is setting your negative volume as it will greatly depend on not only your personal preference, but physical things like weights etc.

My $0.02
Although I've only just found this 'new' valve on top of the right leg, it's not actually changing the amount of travel I'm getting, the spring rate is now able to be alot softer. I was compensating before with compression and lower PSI on the bottom chamber. I've tried running really low pressures up top and still doesn't seem to do much, travel just does not want to go past about 4-5 inches, albeit now it's easier to get through that travel and I'm finding I'm using more compression. Obviously it came with a fair amount of pressure in the top chamber..

It's still got the valve at the bottom of the leg and it's labeled PAR too so I'd say it still has it. I've thought about the negative volume and figured that if I could get in there once unscathed then I'd be able to get in again to muck around with it if I don't like it the first time.

I'll give it another week or two until I've got some spare time to get dirty and play around with it's guts, we'll see how we go till then, not sure much is going to change unfortunately though.
 

WasabiJim

Likes Bikes
yah 08 has the PAR - progressive air spring.

a few points before pulling it out.
- PAR psi should be equal or higher than the top chamber which controls both positive and negative springs. the recommended pressures are way to high. my brother at 95kg plus gear runs his at 140 psi and it does the job

- on the top of the other leg under the rebound adjuster, un screw the D shaped clip in the centre, you'll find yet another air valve! this is the air pre-load chamber, left over from privous designes in their fork range. its serves no real purpose unless you are over 100kg and you need the special marz air pump. at full travel equalise the air pressure here to zero. this may have had air pressure in it boosting the air springs strength, hense preventing full travel

i've found the fork amazing compared to my 36 talas, very active on small bumps yet has a bottemless feel, and that was when set at 150mm. it sounds like a set up problem, i mean come on dude you only just found the main air spring valve. ( not trying to dis you - we all have our moments )
 

RangaRMX

Likes Dirt
yah 08 has the PAR - progressive air spring.

a few points before pulling it out.
- PAR psi should be equal or higher than the top chamber which controls both positive and negative springs. the recommended pressures are way to high. my brother at 95kg plus gear runs his at 140 psi and it does the job

- on the top of the other leg under the rebound adjuster, un screw the D shaped clip in the centre, you'll find yet another air valve! this is the air pre-load chamber, left over from privous designes in their fork range. its serves no real purpose unless you are over 100kg and you need the special marz air pump. at full travel equalise the air pressure here to zero. this may have had air pressure in it boosting the air springs strength, hense preventing full travel

i've found the fork amazing compared to my 36 talas, very active on small bumps yet has a bottemless feel, and that was when set at 150mm. it sounds like a set up problem, i mean come on dude you only just found the main air spring valve. ( not trying to dis you - we all have our moments )
I knew about the other air chamber as well, and have been running it on zero for a while now as I found it horrible with any pressures in there. From what I read in the instructions, which obviously wasn't thorough enough, there was two air valves, one up top and one down the bottom.

I assumed that the one under the rebound knob was one and the one at the par end of the right side was the other...it doesn't really help when Marzocchi give you two air pressure's they recommend, thus this kinda confirming to me that there was in fact only two air chambers..let's face it, their instructions are downright useless.

I'm gonna give them a go for a week or two as I said, we'll see how we go from there, if I decide to remove it I'll probably make a guide with some pics in case anyone else was contemplating doing it themselves too.
 

Wiffle

Likes Dirt
Just to reiterate (and clarify?) what Wasabi said, the bottom valve is obviously PAR; this only controls bottom out resistance, and doesn't affect the top of the stroke; only about the last 40%. The valve on top of this is the main air spring, used to set your sag (and hence spring rate). Set it so you have about 20-25% sag before you play around with other settings. However, before you put any air in this or the PAR chamber (in your case, empty both fully), compress the fork fully and then make sure there is zero pressure in the air preload (other) side. Even if you have zero pressure with the fork fully extended, as the fork compresses pressure will build up in this leg (the seals are airtight) adding to the progressiveness of the main spring and further limiting full travel. This is a good place to start from.
As for the mod, Marz forks are fairly solid and simple inside, so if you have reasonable mechanical aptitude you should be able to remove the PAR piston without too much risk, and most people are reportedly much happier with performance after this is done. You can then (if reqd) use small amounts of air in the air preload side to modify progression rate, although I doubt you'll need it.
Hope this helps. Cheers, Steve
 

JoshyC

Likes Dirt
I knew about the other air chamber as well, and have been running it on zero for a while now as I found it horrible with any pressures in there. From what I read in the instructions, which obviously wasn't thorough enough, there was two air valves, one up top and one down the bottom.

I assumed that the one under the rebound knob was one and the one at the par end of the right side was the other...it doesn't really help when Marzocchi give you two air pressure's they recommend, thus this kinda confirming to me that there was in fact only two air chambers..let's face it, their instructions are downright useless.

I'm gonna give them a go for a week or two as I said, we'll see how we go from there, if I decide to remove it I'll probably make a guide with some pics in case anyone else was contemplating doing it themselves too.
I had the exact same issue with my 07 66sl1 ATA, but after spending a fair bit of time tweaking the pressures they now feel really plush and now Im going through all of my travel.
Im not sure what is and isnt the same in the 08's compared to the 07's but maybe this will help anyway:
-Always have more air in the bottom Valve (PAR) then in the Top Valve (SFA)
-Make sure you fill the PAR then set the SFA.
-Then adjust your SFA to set your sag.
Try to have no more then 30psi more in the PAR then in the SFA

It took me a while to get my pressures right, Marz recommended 115psi & 145psi as starting pressures for my weight roughly. I think I ended up running 35psi in the top valve and 45-50psi in the bottom and now they feel ace. Really plush and I couldnt be happier. According to a few websites Ive had a look at many people are running well below the pressures given by marzocchi aswell.
Just keep messing with the pressures until you do get them right, Dont be worried to go well under the specified pressures as the pressures given are absolute rubbish.

Hope any of that information is relevant to your forks.
 
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No Skid Marks

Blue Mountain Bikes Brooklyn/Lahar/Kowa/PO1NT Raci
Removing the PAR is very easy. DO NOT touch the foot nut on the other side though, repeat, DO NOT TOUCH THE FOOT NUT ON THE OTHER SIDE.
Follow everyones advise on set up first, the PAR chamber in theory is a good idea, it will help to not blast through the mid travel(in theory).
 

mr636

Likes Bikes and Dirt
Removing the PAR is very easy. DO NOT touch the foot nut on the other side though, repeat, DO NOT TOUCH THE FOOT NUT ON THE OTHER SIDE.
Follow everyones advise on set up first, the PAR chamber in theory is a good idea, it will help to not blast through the mid travel(in theory).
i dont know about anyone else, but my mate has followed the above theories to a T, and hes still not using full travel 100% of the time.
the par removal makes it feel like a boxxer fork. very plush, and definately uses all its travel.

the par theory is a great theory, but in practise it doesnt seem to work.
i have heard the air int he par valve heats up, hence the inconsistancy.
 

Wiffle

Likes Dirt
i dont know about anyone else, but my mate has followed the above theories to a T, and hes still not using full travel 100% of the time.
the par removal makes it feel like a boxxer fork. very plush, and definately uses all its travel.

the par theory is a great theory, but in practise it doesnt seem to work.
i have heard the air int he par valve heats up, hence the inconsistancy.
Air will heat up in both parts of the air chamber, not just the par (blame friction). I think the real issue is the reduction of total air chamber volume that occurs with the par. Take it out, you have more air volume, and hence a more linear spring curve.
BTW NoSkidMarks, whats with the opposite foot-nut paranoia?
 

No Skid Marks

Blue Mountain Bikes Brooklyn/Lahar/Kowa/PO1NT Raci
The Par divider is only really thin, it wouldn't take up more than 1% of the overall air space, and the Par chamber itself, would only take up maybe 15% of total volume.
The foot nut on the damping leg needs to be done up and undone with a rattle gun, as there's no way to stop it spinning. It is an aluminum nut, and is expensive, there's no need to touch it, just remove the air side from crowns.
 

mr636

Likes Bikes and Dirt
The foot nut on the damping leg needs to be done up and undone with a rattle gun, as there's no way to stop it spinning. It is an aluminum nut, and is expensive, there's no need to touch it, just remove the air side from crowns.
ive heard that too. it seems really easy to snap the rod that it connects to or whatever too.

thats how mine ended up back at the marz importers, after the LBS snapped it off trying to tightened it.

worked out well in the end tho!
 

Wiffle

Likes Dirt
The Par divider is only really thin, it wouldn't take up more than 1% of the overall air space, and the Par chamber itself, would only take up maybe 15% of total volume.
The foot nut on the damping leg needs to be done up and undone with a rattle gun, as there's no way to stop it spinning. It is an aluminum nut, and is expensive, there's no need to touch it, just remove the air side from crowns.
I know the divider is relatively thin, but remember it only takes adding 2-3mm of oil to the air chamber to make a noticeable difference to spring progression. If it was an insignificant thickness, surely there would be no difference in feel between having the par chamber running at the same pressure as main chamber, or having it removed? Not being argumentative, just don't see any other logical way the mod can have the effect people claim for it. Steve
 

No Skid Marks

Blue Mountain Bikes Brooklyn/Lahar/Kowa/PO1NT Raci
I never tried, but try running the exact same low pressure in both chambers.
The Par divider/piston, is not a very nicely engineered part. Air forks tend to plunge through the mid stroke, the 888ATA doesn't have much adjustable damping to stop this. The PAR set up well, could be beneficial. Try it without it though, it is easy to remove and reinstall if desired. Perhaps remove it until the fork is well run in, and you know it well, then put it back in and go from there.
I'm not saying the PAR works well, and I have no experience of i working well, but I can see it's purpose in theory. Perhaps the air chamber isn't big enough to accept the PAR or to let it work properly.
 

RangaRMX

Likes Dirt
I never tried, but try running the exact same low pressure in both chambers.
The Par divider/piston, is not a very nicely engineered part. Air forks tend to plunge through the mid stroke, the 888ATA doesn't have much adjustable damping to stop this. The PAR set up well, could be beneficial. Try it without it though, it is easy to remove and reinstall if desired. Perhaps remove it until the fork is well run in, and you know it well, then put it back in and go from there.
I'm not saying the PAR works well, and I have no experience of i working well, but I can see it's purpose in theory. Perhaps the air chamber isn't big enough to accept the PAR or to let it work properly.
Well I was more thinking the fact that the PAR chamber is quite small compared to the main chamber might mean that you actually have to run less pressure..not dramatically less but still less. Would this harm the forks at all? I can't see how this would be any worse than taking out the PAR completely.

A smaller chamber with the same pressure will ramp up a shit load quicker, and this could be why you cannot get full travel, perhaps if you started with a lower pressure down there when it comes into the end stroke it'll ramp up because of the heaps small volume will give sufficient progression.

Maybe, but maybe I'm completely off too, just another thought, BTW I've owned these forks for almost a year, so yeah I did feel like the biggest moron ever when I found the main air valve. But not that much difference has come out of it so I'm confused even more!! Here I was thinking I'd struck gold and found the reason my forks were hassling me...

You'd think that Marz would give diagrams or better instructions at least, on how to access the air valves, and as I said before, the whole thing with them giving only two air pressures in all their tables and charts just confirmed to me there was only two chambers..great to see they're concerned about their users understanding their products, and most importantly of all, ACTUALLY BEING ABLE TO USE THEM HOW THEY'RE INTENDED TO BE USED!! I know I'm not the only one who cannot get full travel, and other people have tried a lot more than I have with pressures, so what the fuck Marzocchi!?
 

Wiffle

Likes Dirt
Well I was more thinking the fact that the PAR chamber is quite small compared to the main chamber might mean that you actually have to run less pressure..not dramatically less but still less. Would this harm the forks at all? I can't see how this would be any worse than taking out the PAR completely.

A smaller chamber with the same pressure will ramp up a shit load quicker, and this could be why you cannot get full travel, perhaps if you started with a lower pressure down there when it comes into the end stroke it'll ramp up because of the heaps small volume will give sufficient progression.

I think you may have slightly misunderstood the way the PAR chamber (a floating piston design) works. Because the par piston can move, if you try to put less air pressure in the par than in the main chamber, the par piston will move so as to equalise the pressure with the main chamber; the par chamber will shrink. In other words, it is impossible to have less pressure in the par chamber than the main chamber because of this self-equalising effect. Yes, the PAR chamber will be smaller, and so it will come into effect later in the travel, but it will come on more aggressively, so you will probably end up with a harsh transition point when the PAR starts to activate and a very similar amount of travel.
The best way to get a more linear stroke in an air spring is to increase the overall volume of the air chamber; the pressure increases exponentially as the air compresses, so you want to minimize how much the air gets compessed relative to the overall chamber size. I think you may be best to try the mod and see how it goes. Steve
 

No Skid Marks

Blue Mountain Bikes Brooklyn/Lahar/Kowa/PO1NT Raci
The idea of the Par is too make the main chamber ramp up quicker to stop them blasting through the mid stroke, it was probably an after thought when test riders said it blows through the mid travel.
 

WasabiJim

Likes Bikes
Well I was more thinking the fact that the PAR chamber is quite small compared to the main chamber might mean that you actually have to run less pressure..not dramatically less but still less. Would this harm the forks at all? I can't see how this would be any worse than taking out the PAR completely.

A smaller chamber with the same pressure will ramp up a shit load quicker, and this could be why you cannot get full travel, perhaps if you started with a lower pressure down there when it comes into the end stroke it'll ramp up because of the heaps small volume will give sufficient progression.

I think you may have slightly misunderstood the way the PAR chamber (a floating piston design) works. Because the par piston can move, if you try to put less air pressure in the par than in the main chamber, the par piston will move so as to equalise the pressure with the main chamber; the par chamber will shrink. In other words, it is impossible to have less pressure in the par chamber than the main chamber because of this self-equalising effect. Yes, the PAR chamber will be smaller, and so it will come into effect later in the travel, but it will come on more aggressively, so you will probably end up with a harsh transition point when the PAR starts to activate and a very similar amount of travel.
The best way to get a more linear stroke in an air spring is to increase the overall volume of the air chamber; the pressure increases exponentially as the air compresses, so you want to minimize how much the air gets compessed relative to the overall chamber size. I think you may be best to try the mod and see how it goes. Steve
exactly what i was thinking. and explains how adding oil to the chamber increases progressiveness.

the floating plug that separates the 2 chambers is held in place by a bit of string, i heard that it doesnt take mush to snap it. i cant see how that would cause the loss of travel its just means the plug has the whole leg to move maintaining equal pressure in both top and bottom effectively removing the effect of the PAR.
 
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