Headset for Trek 8900 carbon fiber mountain bike

I have a Trek 8900 carbon frame mountain bike that I love. Recently I bought a new marzocchi fork and now I can not get the fork to stay tight. It has bearing cups already in the head tube. I just wanted to know if anyone has experience with this type of head tube and what type of headset I need to use???
Any help appreciated.
Frustrated

> I have a Trek 8900 carbon frame mountain bike that I love. Recently I bought a new marzocchi fork
> and now I can not get the fork to stay tight. It has bearing cups already in the head tube. I just
> wanted to know if anyone has experience with this type of head tube and what type of headset I
> need to use??? Any help appreciated. Frustrated

We need some more information. Teh 8900 is an older frame (three-tubes carbon, the rest of it
aluminum), and goes back a ways. Does your bike have a threadless or threaded headset? When you say
it doesn't stay tight, is the adjustment coming loose? Have you brought it to a shop to take a quick
look at it?

--Mike-- Chain Reaction Bicycles www.ChainReaction.com