So this is what I have. I picked up a 03 WR450 last week and shouldn't have. To start off with the fuel won't quit flowing out the overflow. I pulled the carb and cleaned it out and it didn't seam to awful bad. The float needle looked good so I figured that there was just some debris in it. Well after the third time back on the bike I narrowed it down to the float seat's "O" ring is bad (if it has one, some say it does). The problem is the seat doesn't come out. I've done some research and some say you can force it out. But I haven't ben able to do that either. I called Keihin and talked to them and they say its not a serviceable part and to by a new carburetor, YUK. But there are to many smart guys out there that I am certain have had the same problem. I thought maybe I could get it out and if it doesn't have a "O" ring I could epoxy it back in. But I don't know if that would work either. So here I am looking for some HELP. If nothing else what other carburetor might I be able to use?