My chain guard broke in the same place where it mounts to the motor. I made a new tab and welded it on and reinforce with some flat strap.
I am not a big fan of not using a chain guard...too easy to get something caught.
Nope, never burned myself...I ride with shorts once in a while, I think my hairy leg's protect me from burns
I did burn the nose of my shoe one time on the muffler.