I just got the '04 WR450 carb I won off of eBay earlier this week and put it in the bike. I was told the bike had less than 200 miles on it and I believe it. The carb looks brand new. I didn't do anything to it jetting-wise except open up the fuel screw about a half a turn. It took a few kicks to get it started (I had to dial in the idle speed a little bit) but it ran fine once I got things dialed in. I revved it but didn't ride it. So far it seems fine just like it is. Has anyone out there done this before? If so, what was your experience with the jetting? Did you have to adjust it or put the needle and jets from the original carb in the new one? I don't want to do this if I don't have to and was hoping to get some advice from those who have done this already. BTW, the reason I did this is because the slider keeps cracking on the original carb and I figured a newer design carb would solve the problem. The slider design is different (it seems to have some kind of damper in the throttle to keep it from slamming shut.) Now that I'm typing this, I have no idea if the throttle stop has been cut so it looks like I need to take a look at it.