My Honda CRF250X has twin chamber forks. For my CRF250X, the center screw controls compression damping. I turn the screw clockwise for harder damping, and counter clockwise for softer damping. The outer screw is an air bleed screw. However, I neither know the design, nor the operation for your QLink XF200 forks.
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Spud
"Never argue with an idiot. He will drag you down to his level, and beat you with experience."
Mark Twain
2015 Zongshen ZS250GY-3 (RX3)
2006 Zongshen ZS200GY-2 (Sierra 200)
2005 Honda XR650L
2004 Honda CRF250X
1998 Kawasaki KDX220
Mods made to my Zongshen ZS200GY-2:
http://www.chinariders.net/showthread.php?t=6894