bleeding

hello friends , i recently bought this bike and im doing some bits and bobs to get it ready for the spring summer season, recently i notice that the radiator gets very hot, and coolant comes out from the overflow pipe....then i had a look if i had weird smoke coming from exaust...no....it was...

Coming from sports bikes i don't tend to use the rear brake much unless it's an OMG moment. However i have noticed something which has now happened twice, the second time whilst coming back from Perigeux in France last week. Having found myself a beautiful "d" road with switchback left and right...