Thank you, Zingshoen.
I am currently using the stock sprocket ratio for the XT225, which is 15T/45T. I definitely notice more power from the extra 27 cc of engine displacement.

Based upon the comments of other XT225 riders, I did purchase a 16T CS sprocket, but I have yet to install it.
__________________
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