with the stock gearing 14-47 you could ride it on the road thats a good compromise for everything... if you want to have a faster bike you have to gear it up to 14-40 or simply add a 15 or 16 sprocket to 15-47 or 16-47 ...
you could simply calculate the rate of the gearing that you want. divide the rear sprocket and front sprocket.
for example: 47 / 14 = 3,357 thats the gearing rate.
if you want a faster gearing the rate must get smaller like: 47 / 15 = 3,133
if you want more torque for offroad or mx, the rate must be bigger like 50 / 14 = 3,571
and now i wish you much fun by testing the right gearing for your needs...