When cleaning the carbs,make sure you keep each float needle in the same needle seat. They wear as a 'matched set' and if you mix them up there is a good chance they won't seal properly and excess fuel will bypass the overflow tube and get into carb throat/cylinder/crankcase. When your bike is on the sidestand,the angle of the fuel level in carb bowl WILL allow fuel to enter carb throat instead of going out the overflow. It may be possible for this to still happen on the centerstand,but I'm not sure. So if you've worked on the carbs recently and your bike smells like gas all the time and when you move it,especially off the sidestand,you get a little spillage out the overflow lines,then mixing the float needles/seats is maybe your problem. Of course,the above problems may be a sign the parts are dirty or simply wearing out ,even if you did'nt touch the carbs. And you don't have to have a failing petcock diaphragm to leak fuel,just the amount of fuel still in the fuel line can drain down,ride after ride,and cause problems. A bad diaphragm just makes things worse. Hope this helps! KK.