I had a RS duke xc Air on my 2004 fisher cake. Good fork for XC riding. I think these first came out in 2002. As far as tuning I remember playing around with different oil weights. I am a big guy at 240lbs and need a lot of PSI and with the stock 5wt oil and high PIS it was too boingy. Think I ended up with 15wt oil which made for a more controlled rebound with the high PSI. Fork lasted me quite a few years and had easy maintenance. Eventually the bushings wore out but that was after about 5 years of use.
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Get out of the gutter and onto the mountain top.
I had a white XC on my 2003 Specialised Epic, only thing i liked about that bike, liked it so much I got a 2004 Duke Race to put on my Yeti ARC, was still working great when I took it off in 2012 the second bike it migreated to, still sitting in the corner ready for action when I need it.
great fork.