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pmk

OZO Pro Trials Rear Shocks, a look inside...

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16 minutes ago, pmk said:

Kind of comical...the advertising says "internal bladder technology"  however, there are no bladders inside these shocks.  In the photos, kind of holding the pose for the OZO sticker on the upper shock eyelet / endcap you can see the two O rings per IFP and the IFP separator pistons under the endcaps.  So no bladders, but there are aluminum IFP with dual O rings to keep the gas and fluid separated.

The British Prime Minister and her Brexit team must have been working for Betor on that product description......very misleading.

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5 minutes ago, oni nou said:

The British Prime Minister and her Brexit team must have been working for Betor on that product description......very misleading.

Ironically, expecting an internal bladder, I was super cautious on disassembling the first shock.  Once I saw the internals, the second was apart in minutes.  No bladder lessened any likelihood of damage while working on them.

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25 minutes ago, pmk said:

Kind of comical...the advertising says "internal bladder technology"  however, there are no bladders inside these shocks.  In the photos, kind of holding the pose for the OZO sticker on the upper shock eyelet / endcap you can see the two O rings per IFP and the IFP separator pistons under the endcaps.  So no bladders, but there are aluminum IFP with dual O rings to keep the gas and fluid separated.

I'd say in the case of those OZO shocks, it's just the result of poor translation into english when they wrote the advertising blurb.

Remember "foam cell" motorbike shocks? I wonder if anyone still makes motorbike shocks using foam blocks instead of bladder/diaphragm or floating piston.

I remember that Kayaba gas (twin and mono) shocks from the mid to late 1970s with floating pistons had "de-carbon" written on them, which I think was a copyright-protected term.

One thing that I'm interested to learn about is a phenomenon happening inside standard Falcon trials shocks. They have no separation between gas and oil. They work noiselessly with gas pressure inside, but if you let the pressure out, you can hear what sounds like gas bubbles going through the damping mechanism when they are worked. How can adding gas pressure make the sound go away?

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20 minutes ago, pmk said:

Ironically, expecting an internal bladder, I was super cautious on disassembling the first shock.  Once I saw the internals, the second was apart in minutes.  No bladder lessened any likelihood of damage while working on them.

How did you position the floating piston on reassembly? If running them body upwards is there any reason that converting to emulsion wouldn't be ok? Seems for a trials shock emulsion would be good. Tricks to reduce damping secret? I put some basic black OZO on my SWM  mainly for appearance but they are surly too slow for good action. 40 LB spring couldn't get themselves pushed back up,50 lb seem good but still slow.

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39 minutes ago, htrdoug said:

How did you position the floating piston on reassembly? If running them body upwards is there any reason that converting to emulsion wouldn't be ok? Seems for a trials shock emulsion would be good. Tricks to reduce damping secret? I put some basic black OZO on my SWM  mainly for appearance but they are surly too slow for good action. 40 LB spring couldn't get themselves pushed back up,50 lb seem good but still slow.

I modified the IFP with a bleed hole that is sealed with a sealing washer and screw after the shock is bled and IFP position set.  I serviced the fluid from the top since I removed the upper eyelet from the shock body.

If you do not modify the the IFP, you could position the IFP to the proper depth, then do not insert the seal into the counterbore.  The excess fluid will leak past the DU bushing until the sealhead seats on the circlip.  Insert the combined oil / dust seal and install the end cap.

As for softening the damping, I installed a bleed shim between the single main shim and piston face, plus altered the far side clamp diameter by adding a small shim above the machined aluminum seat.  Used Motorex 2 1/2 wt fluid.  Yes I know it says fork on it but it is also a very good rear shock oil.

Also, while apart, everything was deburred, and the shafts were polished.  I went a touch lower than typical gas pressure at 125 psi, but was higher than the 60 psi in one and 80 psi in the other shock from the factory.

These shocks now will extend freely, and so far, when installed, the bike feels good and returns to static height.  As I mentioned before, not bad shocks for the money, the price point seems OK for two shocks with springs.  The real question will be are parts available?

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52 minutes ago, htrdoug said:

How did you position the floating piston on reassembly? If running them body upwards is there any reason that converting to emulsion wouldn't be ok? Seems for a trials shock emulsion would be good. Tricks to reduce damping secret? I put some basic black OZO on my SWM  mainly for appearance but they are surly too slow for good action. 40 LB spring couldn't get themselves pushed back up,50 lb seem good but still slow.

Emulsion shocks run body up...Yes, you should be ok.  My own MAR runs period correct Curnutt shock, bodies up, shafts down and are emulsion type.  I would say, but have not tested these shocks as emulsion shocks.  I suspect that what I have seen with these shocks, if you ran them as emulsion type, you could also not gas them since the sealhead is clamped between the clip and the end cap.  No doubt gas pressurized performs better, but no pressure makes seals last longer and less likely to leak.

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6 hours ago, pmk said:

Emulsion shocks run body up...Yes, you should be ok.  My own MAR runs period correct Curnutt shock, bodies up, shafts down and are emulsion type.  I would say, but have not tested these shocks as emulsion shocks.  I suspect that what I have seen with these shocks, if you ran them as emulsion type, you could also not gas them since the sealhead is clamped between the clip and the end cap.  No doubt gas pressurized performs better, but no pressure makes seals last longer and less likely to leak.

Thank you for the info (-: The Ozo Experts do not come apart at both ends like the Ozo Pro do,I was thinking it would be easier to switch to emulsion and have less pressure rise as the shock compresses due to the increase in volume with the IFP out. Maybe run about 10-20 PSI to help the seal at rest but not rise as much when compressed. I am not a shock guy but I assume your mods free up low speed damping more than high speed? I will have to see if Experts are the same inside when I get them apart. Sounds like a project I can do while recovering from shoulder surgery once I need to start moving again this winter. I hit on the idea spring rate and preload spec last time I rode the SWM while doing Trialsmaster duties, I was trying to get good turning and first had the preload up too high which killed stability and made it tiring to ride,Backed it off a single groove and old girl became really sweet in both stability and turning ability. Made her so good I was able to ride it much more aggressively and what do you know,clutch started slipping, New discs are coming from Martin..Forks need work too,feels like internal friction and too high of spring rate,already have Redline Like Water in them and still too slow,have installed Kawasaki Super Sherpa accordion boots in place of wipers which may be adding to spring rate progressiveness but fit like they were designed for them. 

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8 hours ago, feetupfun said:

I'd say in the case of those OZO shocks, it's just the result of poor translation into english when they wrote the advertising blurb.

Remember "foam cell" motorbike shocks? I wonder if anyone still makes motorbike shocks using foam blocks instead of bladder/diaphragm or floating piston.

I remember that Kayaba gas (twin and mono) shocks from the mid to late 1970s with floating pistons had "de-carbon" written on them, which I think was a copyright-protected term.

One thing that I'm interested to learn about is a phenomenon happening inside standard Falcon trials shocks. They have no separation between gas and oil. They work noiselessly with gas pressure inside, but if you let the pressure out, you can hear what sounds like gas bubbles going through the damping mechanism when they are worked. How can adding gas pressure make the sound go away?

More gas pressure means much smaller gas bubbles and thus less noise as the airated damper fluid passes through the control valve(s). 

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