Removed the exhaust studs on my 750F2 before taking the engine out - wasn't a problem, there seemed to be no sign of aluminium on them and they went back in no problem - all OK as I speak (write!).
To remove them, I merely threaded two nuts on the stud I was removing and spannered on the inside one - reverse procedure going back on... hope this helps... oh, and taking them off did make the engine removal soooo much easier!
Cheers, Phil