more often then not....yes. Where is the leak happening?
I've had the same problem. Could be:
1. Float adjsutment (only go bad if someone has messed with it before)
2. float is bad (take float off and stick in a cup of water.....if it floats it's good....if it sinks, need a replacement float
3. Float needle isn't sealing (clean up surfaces of float needle and seat)
4. float is sticking (again, tap on float base with screwdriver handle to get it to quit sticking)
4. sediment between float needle and seat. with float off bike, put cup under carb and turn fuel on, and let fuel flow out.....will HOPEFULLY wash out any crud that's keeping the float needle from sealing.
Lastly, when bowl cover is off, ensure the float moves freely without binding. If it binds, then the pin that holds the float on will need to be smoothed out, straigtened and re-installed.
Maybe the O-ring on the float cover is leaking??
~Joe