Motorcycle Repair: Kawasaki Ninja 500, kawasaki ninja 500, piston rings

Question
I've got a 2006 ninja that I (idiotically) let sit for far too long without winterizing it or anything. I pulled the carbs out and cleaned them hoping that would be enough to get it running. It ran and sputtered a lot and now I can start it but it is burning oil and I have to hold the throttle open past idle to keep it running and it blows almost constant smoke, especially if I open the throttle any. I know the oil would be coming in through the valves or the pistons, so my question is which is more likely the source and if it's the valves,how much of a job would it be to repair, clean, adjust, or replace that element? I know the piston rings would be a pain so I figured I would skip that question.

Answer
The carbs need to be looked at your funning problem.The oil problem is usually from rust building up in the cylinder from sitting. Causing ring of cylinder wall damaged.If you leave your bike sit for extended periods  
fog the cylinders with fogging oil.