Hey, Julio
I don't recall if you installed new rear brake shoes or not, but if you did, they may be in the process of "bedding in". Or the brake adjustment may be a little tight, or you may have
laid hands on after a ride with lots of rear brake action. Friction brakes generate lots of heat that must be dissipated somewhere; the brake drum and hub being the primary cooling surface.
I wouldn't be overly concerned about the rear brake temps. What I'm kinda personally worried about is you sticking your little fingers into very hot places!

Don't do that no mo'.
And Julio, just another tip from an old guy... exhaust headers are meant to be hot. Hands off! [smiley=thumbsup.gif]
Monte