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Old 06-11-2014, 02:17 PM
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Default Bad Free Piston Seal?

     

I installed gold valves in my Showa Twin Chambers from my 2005 RM250 yesterday. I have filled, and bled the inner chamber on both forks. After being compressed, the damper rods will extend quickly on their own until about 1 to 1.5 inches away from being fully extended.

I watched the video of a damper in need of a rebuild here: Leaking Showa Fork Cartridge - YouTube

My dampers extend much farther than the damper in the video. It also does not suck back into the cartridge at all.

Does anyone feel my forks are a candidate for a rebuild, or is this something I should not be worried about?
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Old 06-11-2014, 03:05 PM
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When the seal is bad, the rod will get drawn back into the chamber when trying to fully extend it.
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Old 06-11-2014, 03:16 PM
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Perhaps there wasn't enough oil...
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Old 06-11-2014, 03:38 PM
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I believe I just received my answer after sending an email to JBI:

That is pretty typical of the Showa damper not to completely extend out at the way. The pressure from the pressure spring becomes less and less as the rod extends out.

To get the Showa damper to extend out 100%, when you do the final cartridge bleed by compressing the fork, leave about an inch of the rod sticking out.

Maybe keep an eye on it and let the cartridge sit over night and see if it changed at all.

JB Covington
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Old 06-12-2014, 09:05 AM
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I had this same fear on my forks. It is completely normal for older forks to have that last inch or two move at a snail's pace. As long as they extend at the same rate of each other and that they extend fully, no matter the amount of time, you are good to go.
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Old 06-12-2014, 09:17 AM
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That makes me feel a little better knowing someone else has had the same experience with no issues. Now I just have to hope Race Tech is spot on with their recommended valving so I don't have to tear them apart again!
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Old 06-12-2014, 09:21 AM
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It gets easier the more that you do it. I did both chambers twice because I thought something was wrong when they didn't come out at the same speed. I must admit that I found out the bleeding process is easily overlooked. I stroke those things a TON and even leave them overnight to be sure that there are NO bubbles left. Did you use Race Tech Ultra Slick fluid?
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Old 06-12-2014, 10:51 AM
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I used Bel-Ray 5 wt. I figured there was a high chance that I would be dumping it so I didn't want to spend a fortune on the fluid.
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Old 06-12-2014, 06:37 PM
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Glad you found the answer. Just an FYI, Racetech's fluids are nothing more than re bottled Spectro fluid with a large mark up in price. In my opinion and experience on the ole shock dyno. Silkolene Pro RSF fluid is the best money can buy. It's expensive but more stable than any other fluid I have seen.
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Old 06-12-2014, 06:49 PM
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Quote:
Silkolene Pro RSF
I cannot find this stuff here.....
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