recently installed an HMF slipon for my 09- instantly went from the quietest bike I've ever heard to a LOUD obnoxious beast . I ordered the quiet core but it didn't make much of a difference at all. Had to up the jetting a little from my previous set up: Tried a #125 but ended up with a #128 w/ N1TC clipped in the middle. Around 2.5 turns on fuel screw. Runs VERY nice , butt dyno is sure there are more ponies there. Now just need to tone down the bark a little. Did a search on here and am going to look into getting the QC welded. My friends with their CRF450Xs, etc. don't "get" this bike and wonder when I'm going to go back to a "real bike" but I just laugh, this little bike is just plain FUN!!!

 

I know I know alot of people just don't get the fun part of it. I've had many real bikes but I don't really think I had as much fun on them. Hard to explain isn't it.