That is a great way to enjoy the countryside. The classical route would be to take the Chiantigiana - which undoubtedly is a beautiful trip...however I know motorcycles enjoy some curves in their itinerary so I would suggest heading from Florence to Siena on the famous 222 (aka Chiantigiana), but when you get to Grassina look for a turn off for San Polo in Chianti (blue sign S Polo on the left hand side of the road...kind of sneaks up on you) - road name SP 56 - you won't find that anywhere but maybe a GPS. This road will eventually rejoin the 222, takes you into some less traveled territory and great scenery with some fun curves. You could stop at the Ruffino vineyard located in a panoramic position along this stretch of road.
You can even stop and enjoy a great meal at the Paglietta, a restaurant located right outside of the tiny (very tiny) town of San Polo in Chianti. It is practically on the corner where you turn to go towards Greve in Chianti, which should definitely be the next stop on your itinerary!
Buon Viaggio|