The exhaust temperature you see will scare you. I have seen close to 1400 degrees several times. I knew I was looking at going back to the truck on the end of a rope but, it never happened.
Mid 1300 in the mid range seem to be the norm. Yet, the cylinders and head looks just fine. I don't get it since aluminum melts at 1410 degrees (if I remember correctly).
Don't keep a fixed throttle position going down a trail in the mid range. That's where most of the problems occur, right before the power valves open.
So it seems, the 1250 degrees we have been taught to believe should be our maximum temps completely out the window with these sleds. Yet, they seem to live on just fine (most of the time).