Author Topic: Shock internal gas (air) bags.  (Read 2728 times)

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Offline John Orchard

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Shock internal gas (air) bags.
« on: February 28, 2023, 08:29:49 PM »
I've never had a freon gas (S&W used term), nitrogen gas bag shock apart before, they have a sealed bag of gas that compresses to allow more capacity as the shock-shaft fills the shock body. Anyone know where I might find such a thing?

QA1 in the States makes some in various sizes for their car speedway racing shocks, I've contacted them, just waiting for a reply to see if they have something that will work. I'm just considering possible alternatives at the moment.
« Last Edit: March 03, 2023, 08:51:54 PM by John Orchard »
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Offline John Orchard

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Re: Shock internal gas bags.
« Reply #1 on: February 28, 2023, 09:01:27 PM »
« Last Edit: March 01, 2023, 11:23:00 AM by John Orchard »
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Offline Hoony

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Re: Shock internal gas bags.
« Reply #3 on: March 01, 2023, 08:14:28 AM »
Ha, check this ....

you forgot something "Old Timer"    :)
Long time Honda Fan, but all bike nut in general, Big Bore 2 stroke fan.    http://www.youtube.com/watch?v=XJoKP6MawYI
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Offline John Orchard

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Re: Shock internal gas bags.
« Reply #4 on: March 01, 2023, 11:23:49 AM »
Ha, check this ....

you forgot something "Old Timer"    :)


Just a test to see if you're reading my posts :-) he he.
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Offline John Orchard

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Re: Shock internal gas bags.
« Reply #7 on: March 03, 2023, 07:46:38 PM »
Ok, so I had an old pair of S&W Stroker shocks sitting the rubbish bin for about 10 years, they were shagged but I could not come at throwing them away. So here they are cut open ....



S&W quoted these as having the 'Freon Cell', me always thinking these were some kind of high pressure thing ..... no they are just sealed plastic bags of air, these just allow for the displacement of oil as the shock shaft enters the shock body, man you could just use bubble-wrap if the plastic didn't break-down in the oil (and it probably wouldn't) ..... in fact, a Glad sandwich bag heat sealed on the four sides would do it!.

And here are the 'Freon Cells' out of the S&W's, it looks like the dirty shock oil has migrated into the bags but they are still holding air, and in a pinch I'd reuse them.




I am also currently rebuilding a pair of Honda CR125M3 rear shocks, they are 'twin wall' and there is easily enough room to slip in these gas bags in between the outer wall and the piston tube, therefore allowing the CR shocks to be run upside down if wanted.

These 'gas bags' are used in many mas produced family cars, so if you have any old car shocks laying around, cut them open for the bags :-)
« Last Edit: March 03, 2023, 08:51:08 PM by John Orchard »
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Offline pokey

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Re: Shock internal gas (air) bags.
« Reply #8 on: March 03, 2023, 10:07:07 PM »
The great gas fiasco. Glad you posted the pics

If its gas it had to be good right ? But it was just an emulsion shock with a sandwich bag apparently filled with a gas called freon that was suppose to limit foaming by somehow absorbing through the special plastic membrane any air that had had entered via the seal and stop foaming which deplete shock performance. I cant see any plastic being able to react that fast and work out whats gas and whats oil and they didnt either.

A pair of curnutt koni or S&W  would perform way longer than the bag shocks because they had better valving. it was and remains that simple. One short moto and the bag shocks were spent. 10 k on an enduro and you had good springs as they came with decent springs and SFA dampning so you spent the next 20 mins missing braking points and trying to hold a line and thinking  you may have spent too much on the sticker that came with the kit but the shocks did look flash and your fridge  did have a new sticker.
 
People still seek them out the same as brocky's magic box that did SFA too.






Offline John Orchard

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Re: Shock internal gas (air) bags.
« Reply #9 on: March 03, 2023, 11:08:06 PM »
Yes, true 'gas' shocks just keep the oil under pressure, it's the shims & valving that create the shock absorber action. Some shocks separate the gas from the oil with a bladder or floating piston (DeCarbon), so that the oil does not become emulsified, plus you can run the shocks either way up.

These 'gas bag' shocks just allow the shocks to be sealed without any air or gas floating around in there to aerate the oil, when reassembling the shock, the oil is filled to the top of the shock body, with the rod extended, once sealed, any oil displaced by the insertion of the rod is absorbed by the compression of the gas bag, or closed cell foam. If the valving is correct, this design is ample for short vmx events.

I guess on a true 'Gas' shock, 150psi of pressure on the oil will reduce the chance of aeration more than not having that pressure.
« Last Edit: March 04, 2023, 02:33:52 PM by John Orchard »
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Offline Hoony

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Re: Shock internal gas (air) bags.
« Reply #10 on: March 04, 2023, 09:20:07 AM »
People still seek them out the same as brocky's magic box that did SFA too.

the energy polarizer ( is that the one) i remember seeing that on the 6 o'clock news and thinking................... what a load of crap!
he lost a lot of integrity over that one
Long time Honda Fan, but all bike nut in general, Big Bore 2 stroke fan.    http://www.youtube.com/watch?v=XJoKP6MawYI
1985 Honda CR500RF "Big Red"
1986 Honda CR250RG
2005 KTM 300EXC "The GruntMeister" ( I love that engine)

Offline PeterC

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Re: Shock internal gas (air) bags.
« Reply #11 on: March 04, 2023, 04:57:02 PM »
Did any of the Marzocchi external reservoir shocks have gas bags?.
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Offline John Orchard

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Re: Shock internal gas (air) bags.
« Reply #12 on: March 04, 2023, 06:06:20 PM »
Did any of the Marzocchi external reservoir shocks have gas bags?.


I wouldn't expect any shock with a piggy-back or remote reservoir to use a gas bag, it was designed for twin-tube no reservoir shocks.
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Offline John Orchard

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Re: Shock internal gas (air) bags.
« Reply #13 on: March 06, 2023, 10:22:03 AM »
Got some new bags, $10 each, from these guys in NZ https://www.cardwells.co.nz/product/qa1-gas-bag/
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Offline LWC82PE

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Re: Shock internal gas (air) bags.
« Reply #14 on: March 06, 2023, 09:48:49 PM »
Marzocchis had bladders and pistons. You can by new freon cell shocks from Progressive suspension. They are S&W's just rebranded when Progressive took over the S&W shocks in the 80's. I have seen people buy new Progressives and paint the spring seats yellow and blue like the S&W's were.

https://www.qa1.net/ do the new gas bags but it seems the one you want is sold out everywhere (i just had a look around)
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