It will make all of the gears taller. It's of no use except to gain mpg if cruising, but it will never pull the higher gearing in top to the redline, assuming you don't reduce teeth on the rear sprocket.
Why do you want to do it?
It's not falling off, it's an upgrade opportunity.
Many thanks for the advice gents, i went up a tooth as the bike is now tuned so thought it may work out , but im thinking of dropping back to the 16 thanks again.
Ok so some further experimentation and more ridding ive decided to stay with the 17th i think it will spend a lot of time on the back wheel with a 16 even in 3rd its a bit skity under heavy acceleration.