I'm a little out of idea now... My bike leaks so much fuel from the overflow tube when leaned on the left side (starts to pour at about 15 degree). There's no leak what so ever when I lean on the right side. So I took the carb out of the bike and I followed this guide to adjust my float height: http://www.allthingsmoto.com/forums/f-15/how-set-your-motorcycle-carburetor-float-level-more-commentary-13608/. The float where mis-adjusted - they were set to 7.5 mm when the carb was upside down. So I fixed that and made it so that it's at 7.5mm when only touching (needle spring not compressed). That didn't help. Still leaked a lot. I took the carb out again and replaced the needle valve and seat seal. Same thing still happens. I've sunk the float in water. They don't seem to be a problem - no air bubble and they float good. So floats are good and adjusted, needle and seat are new. But it seems like there's still to much fuel getting into the bowl?