Got NOS Forks, dont seem to have dampening?

[pcweber]

So I picked up a pair of NOS forks for my Nomad. (mine were bent) I can tell they are true NOS as they have no sign of even being mounted. Anyhow I noticed when I pressed down on them on the floor they did not have much more than spring action. No real oil resistance or dampening. When i pulled my installed ones they had a definite dampened feel. So, I pulled the plug on one and it had oil, put the oil back in, put them on thinking I needed to cycle them. Well I just the on and held the front brake and pumped it for 5-10 mins, still bouncy. Any ideas? (it is a 99 Nomad)

[dshelly]

Are the seals ok? Maybe change the oil to a heavier weight. I changed mine to 20W, much better.

[ringadingh]

Try 20 weight oil as mentioned, maybe they don't have the correct amount of oil in them as well.

[pcweber]

ringadinga,
I know there is a science to measuring the fork oil after adding. I also noticed in your thread you refer to adding additional oil volume. Is there a quantity/ amount of oil you came to after your research?

[RACNRAY]

These are simp[le damper rod forks so not much can go wrong. I would disassemble them to inspect a few areas.
At the top of the damper rod is a piston, these usually have a groove in them with a floating piston ring, usually made of some type of plastic. If this ring is damaged, broken, scored or stuck in the groove it will allow oil to bypass the dampening rod orifices. Also inspect the inside bore of the chrome tube. Since it is made of steel check for rust. This rust will damage that ring and also not allow that ring to make good contact to the inside bore, thus again allowing the oil to bypass the damper rod orifices.

If all this checks out ok then there is the possibility that the oil has broken down. Did the oil appear thin? If these are new forks they should operate as new forks, so the exact cause of their loss of dampening needs to be detirmined.

HOPE THIS HELPS

RACNRAY

[smokey]

while they may have had oil coming out when you pulled the drain plug, they may not have the correct amount of oil in them, I would recommend taking the drain plug out and also the top cap, and see how much actually comes out. What you saw may have just been residual oil if the previous owner had drained them. By the way I use the simple method of determining how much oil, I simply drain the forks into a container and see how much comes out, I then replace it with the same amount or the amount stated in the manual if it is a little low. Wife is still trying to figure out the oily film in her pyrex measuring cups.

[pcweber]

Yea, going to try that tonight as I suspect the new ones not to have enough/ right amount. I will drain the old ones.

[ringadingh]

I can't remember the volume, but I used a measure cup at first then topped it up as per Gadgets Fixit sight by using the measurement method. When I just put in the proper amount with the measure cup it seemed low to me.Thats why I topped them up.

[dshelly]

14.8 oz. when just changing oil or 17.3 oz. completely dry.

[pcweber]

Here is a question. Can I remove the top plug with the forks on and then take out the allen bolt from bottom to drain them without removing from bike? Will that allow all oil to drain out of forks?

[ringadingh]

No, they won't drain properly if at all. That allen bolt is what holds the cartridge in the fork tube bottom, it is also were all the crud settles in the fork tube. You should take them apart and clean them then fill with new fork oil.