Charles Warren, whose 301-yard driving average ranks ninth on the PGA Tour, shot a 9-under-par 63 and was two shots back in second place at 10-under. His round was Friday's best in relatively calm morning conditions before winds gusting up to 30 mph picked up in the afternoon at the 7,472-yard, par-72 Montreux Golf & Country Club on the edge of the Sierra Nevada.
Argentina's Jose Conceres, who made a hole-in-one en route to an opening 64, dropped back to third place with a round at even par for an 8-under 136.
Australia's Steve Allan followed an opening 65 with a 72 Friday for a two-round total of 7-under 137, tied for fourth with Reno resident Todd Fischer (68), Jason Dufner (70) and former Virginia Tech teammates Johnson Wagner (69) and Brendon de Jonge (70).
A group of six players another stroke back included Corey Pavin (71), Shaun Micheel (70) and Jason Gore (72).
Defending champ Will MacKenzie shot a 73 but made the even-par cut at 5-under 139, as did Steve Elkington, who shot 70 on Friday. Tadd Fujikawa, a 16-year-old high school junior from Honolulu, shot a 71 Friday but missed the cut at 7-over par in his professional debut.