Fork Fluid Question

43 replies to this topic
  • MikeOK

Posted September 01, 2001 - 05:15 PM


I've used Silkolene 5W with goos results. Changed it today after about 15 races and it was really cruddy, so I think I'll start changing it more often.

  • Ga426owner

Posted September 01, 2001 - 06:45 PM


Silkolene 5w is in my forks at 100mm I am not terribly impressed with this oil. Although the seal head shims have my curiosity! Maybe my issue is that too much oil flow may be the issue. Just how hard are these to check/remove???????
a question for both the Dave's & ScottF????

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  • MikeOK

Posted September 02, 2001 - 05:44 AM


I have noticed that the Silkolene seems to get dirty alot sooner than whatever they put in it from the factory. I am still on the stock seals on my '00 and I've never taken my forks down any more than you have to to change the oil. No seal leaks yet and I race moto and I'm a tubbo so I work them fairly hard (210 lb's ready to ride). I have read about the ATF before and I might try that next change and go ahead and dive down to the the innards of the forks and clean them real well...

  • DaveJ

Posted September 04, 2001 - 09:29 PM


In my opinion the seal head does flow oil around the seal head shim stack. If this flow varies for whatever reason, the oil flow rate through the mid-valve would change. More flow past the seal head would equate to less flow via the mid-valve.

In the past, I tested the flow rate around the seal head between the two forks. One was dramatically more than the other. This could have been caused by the shims going bad, or it could have been caused by excessive particles in the oil. I don't know which.

When you install the bottoming cones from C-Cycle, the entire factory seal head is replaced. However, you utilize the existing bushing from the factory seal head on the bottoming cones.

Which would mean that you are essentially getting the same flow rate past the bushing between the two configurations, but with the factory seal heads you're getting more flow via the seal head stack.

Which would mean that the bottoming cones would flow more oil through the mid-valve, which could cause it to 1. fatigue sooner, 2. make the ride more aggressive. Both are assumptions.

In either event, I like the idea of running a restrictor plate with the bottoming cones. Seems to shore things up, eliminating the variances in the flow around the bushings and allowing one to concentrate on the ride quality via the mid-valve and compression stack. One less variable so to speak. the seal head rebuildable? Not really. I mean, anything is rebuildable, but this is not worth effort nor would the result bring you much return. Keep in mind that the factory seal head is forged together, which requires a lot of metal removal to get the thing apart. This means you somehow have to replace what you removed.

As discussed earlier, most of us should be switching over to a bottoming cone restrictor plate configuration. Then the division begins with mods or removal of the mid-valve in accordance with the type of riding we are doing. The SuperCross only guys should most likely run a modified mid-valve based on one's needs and the track design. The hard-core trail junkies should pull the thing and run a check assembly.

I have my mid-valve removed and still SuperCross, but I also run the ultra-adjusters providing greater ease on setting up for the two styles of riding. However, I have yet to get the "perfect" suspension feel on the big tracks as I have on the trails.


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