Recently picked up a 2001 400ex. It was bone stock and had very little use. Carb kept leaking from the overflow so I rebuilt it. That fixed it for a little bit, but the problem returned. It needed to be re-jetted after installed a slip-on so I took it apart cleaned it a little bit and tried again. Still leaks, from both of the drain hoses at times. So yesterday I took it apart again, all the way down to the last bolt. Sprayed out everything I could think of and blew it out with air as well. I also found some fuel in the oil, but that was to be excepted for the situation. So I changed the oil and re-assembled the carb very carefully and was sure to follow the manual to a T. Took it out and rode it for about 30 minutes. It ran fantastic. No sputtering like before and I didn't notice any fuel leaking out or rich symptoms. I decided to let it sit for a few minutes with the petcock on to see what happens and welp, you wouldn't guess. But there it was... leaking from the overflow again. What am I missing here guys? everything inside of the carb is new except for the float and even that has been swapped out between another spare carb I have, (It made no difference).
