Hi - I left my 1999 YZ 400 in the garage for about one month (before that it was working perfectly). I have had the bike since new in 99 - used it for many enduro's and MotoX events and amazingly this is the first problem so far. All I have done is standard servicing. When I turned the fuel knob on - it started leaking out of the carb overflow. The bike would not run at all - (obviously far too rich). So - I checked the float / fuel level - far too high. But why would this change all on its own? I replaced the float needle and seat. I checked the float was not binding. I checked the float was not punctured. None of these things made any difference. I then bent the float tab to change the float level - I had to bend it quite a lot. It now has nearly the right float level (I cant bend it anymore) and just about runs - but very rich. Occasionally it still leaks out of the carb. I have a feeling that I have missed some underlying problem - why would this suddenly occur? Any help or suggestions?