I dont ride in real cold weather, but this is how i warm my bike up everytime. Ill start it, let it idle, check my tires add air if needed, put my riding gear on which consists of gloves, helmet, googles, ill feel the pipes, if there startin to get pretty warm ill hop on her and take it easy for a couple minutes, and then let it rip. Common sense and you will be alright.
Cody