The gate drops on round 2 Race 1 tonight from Jerry's World in Dallas, Texas. Yes, I realize it's actually in Arlington but the Cowboys have been my favorite NFL team since the late 70s so as far as I'm concerned. It's the 2017 Dallas Supercross!
The race video on Daily Motion was broken into 4 parts, which includes the heats and mains of both the 250 & 450 classes. If you just want to watch the 450 main, I'm pretty sure it starts towards the middle of Part 3. Good luck!
The 2017 Dallas Supercross with Ralph & Fro.