Following are some photos from the AHRMA National MX at Chehalis, WA, 12 August 2007.
This is one of the biggest Vintage MX events in the U.S. with 400+ entries.

This is what "The Farm" is all about - lots of natural terrain.

Waiting for the action to begin.

Pair of Rickmans - Gold Star and JAWA

Matchless Rickman

Triumph and BSA at the ready.

Mike Johnstone gets the white flag on his B50.

Dallas Nyblod borrows a Rickman JAWA.

Doug Grant on the AJS.

Web editor on his Classic 500 BSA.

Not exactly British, but Martin Spriggs' NSU Special does use a BSA frame.

Jim McDannald on his 380 Greeves.

Rob Poole leads two B40s in Premier 500.

Premier Lightweight Greeves of Gary Collman.

Tom McCallister on his Cotton.

Pat Riley, Classic 500 BSA.

Rick Downing, yet another Classic 500 BSA.

Thanks to Reese Dengler and Nancy Richards for some of the photos.