Greetings everyone!  New to the forum, hope someone can help and I can return the favor someday.  We have a 2005 GS500F.  2400 miles.  Fuel is overflowing from the airbox drain.  Pulled the carbs, cleaned and set the floats.  Reinstalled and without the airbox installed, started the engine.  Gas will come out of the hose on top of the engine (rear cylinder cam cover) after about 20-30 seconds.   Never any problems before.  No modifications to the bike at all.  We have a manual on order, but the weather is finally nice here in NE Ohio and wanted to ride.  Help would reallly be appreciated.

John

Are you speaking of the valve cover vent hose?It may drip oil.There's no way for fuel to get in there.The engine constantly vents hot crank case air out of the vent hose.Some times it picks up oil vapor and mist,and that is expelled into the air box.If there is much more than a couple drops in there,you have serious engine damage.Maybe a colapsed ring or bad valve stem seal from improper break in.A bad valve stem may allow some fuel into the top of the head and bad rings will cause excessive pressure in the crank case.That's all I can come up with.

I was also confused by the problem description 

If possible, a photo would help.

I had a carb needle valve leak once on the 97 GS.  Besides the air box drain leaking gas the engine sump was about a pint overfull with gas in it.  Leaks thru the intake valve and drains down into the crankcase.  Check your oil level and smell it for gasoline smell, change oil if it got gas in it and carbs are fixed now.

The oil does appear to have gas in it, and the level was high.  Yes, the gas was coming from the valve cover vent hose.  Is it possible the engine flooded, leaked gas past the rings into the crankcase, then blew it out the vent hose?  The air box had gas in it also.  I will try to get some photos posted.