yeah that sucks bro. when i first built my cheetah in '05, my first trip to the dunes a plug came loose and the motor ran lean. i was able to run it the next dune trip, but the damage was done.. i had to have it bored, nikasil'd etc.. very costly (when they re-nikasil, the process takes the polish off the cylinders.) but after that i never had any issues, and i run the hell out of the motor. new pistons, reeds, and clutches in '07.
i'm curious what my motor does on pure evil's dyno. did you have knobbies or dyno tires mounted?