The American Motorcyclist Association (AMA) has announced changes to the schedule for the 2008 AMA Flat Track Grand National Championship. The half-mile GNC Twins event planned for April 5 in Tucson, Ariz., has been cancelled.

"Unfortunately, our program no longer fit into the plans of the facility's management," said Ken Saillant, AMA flat track director. "Obviously, we're disappointed that we can't bring the exciting show of AMA Grand National Championship racing to fans in the Southwest with this event. We will do everything we can to return to the region as soon as possible."

With the cancellation of the April 5 event, the next round on the AMA Grand National Championship calendar is Memorial Day weekend. To be held May 24-25 at the Illinois State Fairgrounds in Springfield, Ill., the weekend will feature GNC Singles bikes taking to the TT track on Saturday and GNC Twins racing on the storied Springfield Mile on Sunday.

"Springfield perennially serves up some of the best racing you'll see anywhere. Period," Saillant said. "Last year, the Springfield Mile delivered two truly historic races-Kenny Coolbeth's dominating performance on Memorial Day weekend and Chris Carr's photo-finish win over Coolbeth on Labor Day weekend in one of the closest GNC Twins races ever. We expect nothing less from Springfield this year."