A couple of days ago I noticed a smell of gasoline next to my bike while i was letting it warm up. Then i looked down on the left side and I can see a gas leaking down from somewhere. I took a closer look and it's out of a tiny open house up near the carburetor cover. The hose looks like it's supposed to be there. When the bike is off, the rapid dripping stops. Any idea of what and why this is happening??

 

sounds like its leaking out of the float overflow. one or more of your floats are probably sticking or adjusted improperly.

 

How can I fix that?? Probably have to open up the carbs right??

 

unfortunately, yes. do you have a manual, or confident on amking the repairs yourself?
when you get to the carbs, leave the metal airbox base attached to the carbs, and pull all four carbs off as one peice. this will minimize any changes to the syncronization. you can pull the float bowls off and inspect the floats. make sure they pivot freely and the needle valve doesn't look worn, or nothing blocking it. check to make sure the level of the float when the valve closes looks the same on all four carbs. the manual says the height of the float should be 8mm from the carb flange, when the little flange just starts to touch the needle.