They are open 24 hours starting usually at 6:00 pm for members unless there's a Friday private track rental, that can push everything an hour or more back.
Welcome aboard, I'll be out there coaching, if you need something look for the 112 R1's behind a super c and 24 foot white trailer at the hot pit entrance.
Last year in the endurance race on a Westby stock 1000 r1 motor we were seeing 168-171 depending on rider and drive. That was gps derived through the yec onboard data acquisition. You can draw your own conclusions.