kinda does sound like a leaky crankcase seal, but cant hope for the worst! lol throw some new plugs in there make sure your float heights are correct. See if your getting gas to the carbs, check spark on both plugs. Crank it over a few times with the ignition off to load up the cylinders a bit then try and fire it up. Make sure you have the choke tube connected between the carbs and both of them synced. Compression is always a must also! check your head nut torque, should be 22ft/lbs on each. You would have noticed if you were burning gear oil, woulda been a pretty smokey ride! If you HAVE to shoot a shot of starting fluid in there, its not good but just a little bit wont hurt ya. DONT use it every time!! Might also need to bump up your pilots, but if you said it ran before than just do all these other checks.
Let me know how it goes!