Originally Posted by
onespeedbiker
If the frame is titanium and the fork carbon (he didn't say of the steerer is steel or not), and assuming fork is all carbon, as the OP asked, where would the rust come from?
Bearings.
I had exactly this problem on my Litespeed with an aluminum steerer. The top bearings were shot and lots of brown crap coming out. Not sure why the top, I rarely ride in the rain or wash the bike with a hose. The bottom set were indexed a bit, but in reasonable shape otherwise.