Bought a 92 600 f2. Sat for a couple years. Bought new carbs(used from ebay) do to diaphragms bad. Valves doesn't seem to be sealing. Am I able to adjust still in frame?if not, How do I remove the valve cover? Can I remove head with engine still in frame? If my piston rings are sticking, can I put something in engine to break it free.

 

You can do the valves clearance with the engine in the bike however if I remember right the head is the front mount that holds the engine in, I don't think it would be a good idea to try to do it in the frame. You might find that the valves need lapping to seal again, that has to be done with the engine out the frame
Good Luck