At the P1 Kart Circuit about 20 miles south of Tucson, Ariz., the desert air is filled with the whine of racing-grade go-karts tearing around a serpentine track at 65 miles per hour. These aren?t Disney Land fun rides. Beyond the boundary fence, Rob Ashley tinkers with his own racing kart, which was damaged when a recent cold snap cracked his water-cooled, single-cylinder, 125 cc engine.












