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PostPosted: Sat Oct 10, 2015 12:25 pm 
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Joined: Thu Sep 17, 2015 11:42 pm
Posts: 15
I know there's info on here about the finned shocks used on the 73/74 bikes, but does anyone have any info about the gas charge shocks used on the 1976 bikes( with the necked down reservoirs, looks like a bottle)? I bought a pile of them cheap, but they are pretty rough and will need some work.


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PostPosted: Thu Oct 15, 2015 9:34 pm 
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Joined: Thu Sep 17, 2015 11:42 pm
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Anyone?

I'm trying to figure out how these things come apart.

Might just attempt pull it in two with a hydraulic engine lift crane and some chains and see what happens. The shaft bushing must be pressed in?


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PostPosted: Fri Oct 16, 2015 9:09 pm 
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Joined: Fri Jun 02, 2006 11:12 pm
Posts: 159
Location: Salinas, CA
Though I haven't worked on these particular style shocks, usually you press that seal head inward to reveal a rentention circlip. Pull out that circlip and the shock should come rigth apart.

Make sure to release any air pressure first. At around 150psi, they can blow the piston assembly pretty powerfully.

Enjoy,
Jon


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PostPosted: Sat Oct 17, 2015 11:50 pm 
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Joined: Thu Sep 17, 2015 11:42 pm
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I figured it out.

For future reference-
The seal head is just pressed into the shock body, No clips. I used 2 chains and a engine crane to separate them as they had rusted together.

The shock innards are very simple. Inner steel cylinder tube with the rebound valving on the bottom, an inner piston that has the compression valving then the top out spring, Guide bushing, then oring,seal head and the dust seal.


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PostPosted: Thu Oct 22, 2015 9:02 am 
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Joined: Sun Nov 30, 2008 12:10 pm
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Location: Connecticut, USA
Cool! Those must be emulsion-type shocks (I always thought they had a bladder inside). I imagine you can just rebuild them without nitrogen using two non-leaking seal heads, which would probably last quite a while without the gas pressure on them. Those innards look very similar to the 360's. I'd be sure to check the one-way valve(s) - on the 360 there's one in the piston and another in the bottom of the inner tube IIRC.

Ray

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'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric


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PostPosted: Sat Oct 24, 2015 4:49 pm 
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Location: Wuppertal/Germany
ray, they won´t do a good job without the gaspressure. :wink:

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82 Bultaco Sherpa 340
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PostPosted: Sun Oct 25, 2015 6:42 am 
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Joined: Sun Nov 30, 2008 12:10 pm
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Location: Connecticut, USA
Quote:
ray, they won´t do a good job without the gaspressure.

If they had bladders I would agree with you, but they don't - they're just a simple low-performance emulsion design where oil/nitrogen mixing is accepted as part of the design parameters. With modern shock fluid and used in non-racing applications where heat buildup / oil cavitation are not serious issues they should work OK without pressure, and if one does plan to race the bike, they should be replaced (duh).

Ray

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'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric


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PostPosted: Sun Oct 25, 2015 9:00 pm 
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Joined: Thu Sep 17, 2015 11:42 pm
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Well the bike will be raced. But compared to the shocks that were on the MT stock, these are like a magic carpet.


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