Monster Energy/Pro Circuit Kawasaki's Ryan Villopoto, who crashed out of last weekend's main event, was the fastest overall in the Lites class, putting down a 48.369 in the second seeded practice session.
Last week's winner Trey Canard of the Torco Racing Fuels Honda team was second fastest overall with a 48.874.
Canard's teammate Josh Grant was fastest in the first practice session, besting his teammate's time late in the session. He's third-fastest overall with a 49.012.
Yamaha's Josh Hill surprised with the fastest overall time in the 450cc practice, set in the second session. His fastest lap was a blistering 46.429.
San Manuel Yamaha's Chad Reed was second overall, also with a time from the second session, with a 46.514.
Torco Racing Fuels Honda's Kevin Windham was the fastest rider in the first practice session, with a 48.015, but everyone went faster in the second session, and Windham was third-fastest overall with a 46.557.
Rockstar/Makita Suzuki's Ryan Dungey has had a bit of a rocky start in the 450cc class. He was fastest in both non-seeded practice sessions, and sixth-fastest overall with a 47.598, but he also suffered two pretty big getoffs - one in each session.
Rumors circulated the pits after the first practice that MDK KTM's Billy Laninovich was pulling out of the race after a crash he suffered in the whoops, but he returned for the second session and will be racing tonight.
Tune into www.supercrossonline.com tonight at 7 p.m. PST to listen to the race live.