Motorcycle Repair: Raw gas coming out of the exhaust, honda vfr, exhaust pipes

Question
Bike was running extremely well, stopped at the store to pick up something. When I came back out and started the bike, it was hard to start and when it finally started a lot of smoke came off the exhaust pipes and the bike won't stay idle at all. I had to keep reving it up so the engine will stay running. When I got home, I tried to check what caused the bike to suddenly run terrible. I noticed that as I rev up the engine, raw gas was just spitting out of the exhaust pipe.The bike have dual exhaust ( 4/2 ) and gas is spitting out of the one from cylinders 1 & 2. Bike is a 1897 honda vfr 700F.
Definitely carburetion promlem, but what would cause it to all of a sudden do that without any
warning?

Answer
Hi Rusty,

Q:  "... Definitely carburetion promlem, but what would cause it to all of a sudden do that without any
warning?"  

A:  Some mechanical failures have immediate results without indication of a problem. I suspect the needle valves are worn, varnished, or otherwise not working properly. Check the airbox and engine oil for evidence of fuel.

Respectfully,
Mark Shively