Did my research, and couldn't get a EXACT answer.. Bought my first 2011 WR450F 4 months ago, and am loving it. Only complaint I personally find, is it's too speedy. Not a fan of doing over 140+ (Kms) on dirt road. Anyway, I'm looking for more power then speed, my friends tell me the easiest way is to change the sprockets. I was wondering what would have the most effect on dropping/adding teeth. Should I start with dropping a tooth or two on the front, or adding a few on the back. I am currently running the stock 13/50. Also, does gearing the bike down have any damaging effects on the bike? Thanks guys. Riley.