Standard sprockets are: front 15 teeth / rear 45
By changing the front sprocked to a 14 teeth your bike will gain a quicker acceleration however the moment you mess up with sprockets your speedo will give unaccurate readings, hence you might want to be careful when going past a gatso. To compensate for that you could fit a speedo healer but it has to be calibrated by someone who has a rolling machine and instruments to measure it. Personally I wouldn't bother with it, too much hassle.

If you want to learn more of the effects that a change in sprockets will do to your bike try and experiment with the attached spreadsheet.