Here are some fast lap times
from a 2009 AFM Race at the Infineon AFM track configuration:
Superbike 750, Lenny Hale, Yamaha '08, 1:42.628 (Yamaha YZF-R6?)
Formula I, Lenny Hale, Yamaha '08, 1:42.745 (Yamaha YZF-R6?)
Formula 500 Twins, Allen Erkman, Suzuki '99, 1:51:640 (
Suzuki SV500?)
Superbike 250, Ed Thompson, Suzuki '08, 1:54:951 (Suzuki RMZ450?)
"The following 4-strokes may run down one class in Superbike: Singles, Twins and 675 cc triples."