2000 Yamaha YZF600R front tire size

I am finding it increasingly difficult to find a 120 60 zr17 front tire for my bike.  I am considering changing over to a 120 70 because Pirelli is limited on the 60's.  The Pirelli Diablo Rosso is my tire of choice I don't really want to change them or the bike.  Besides fender rub what else can I expect or need to change along with the tire?  

Your bike's ride height in the front will change, because the taller profile tire will raise the front of the bike. You can either take some spring preload out of the front fork, or raise the fork tubes a few millimeters in the triple clamps. Preload is easier, obviously.

To tell you the truth, we've never liked the 60-series profile front tires. While the steering at lower speeds might be easier, their ride and grip levels when riding aggressively left a lot to be desired. You'll be much better off with the 70-series tire. There's a reason why manufacturers no longer spec that front tire on their latest sportbikes anymore.