engine not used for years - problems?

[Renevator]

I'm wondering if I need to rebuild the engine to some degree.

 

I've had my vfr750fr completely dismantled for years (about 3). The engine is out of the frame, drained of fluids, with carb off and respective carb holes plugged with rags. I didn't plug the exhaust holes, just left to air, and the bike had been stored in a dry garage, but with no heating.

 

Would exposed exhaust ports, No oil or coolant in it (oil cooler and pipes are also off) and leaving it completely idle done any lasting harm? And is there anything else I'm likely to have buggered up by leaving it stood unused for so long? Would condensation or slightly damp air have done harm to the valve seals in any way, or would the clutch, Pistons or anything else sat in the same position for ages require attention?

My aim is to rebuild the bike but ideally not the engine, ( I appreciate carbs and all fuel related components need a clean/renew) but just wanted to check I've not been a total bozo and caused more problems by leaving the engine like that. Thanks.