There are 4 main classes:

Superbike- the top class, limited to 1000cc's, pretty extreme engine and chasis modification allowed

Superstock- up to 1000cc's, bikes similar to what we ride on the street, modifcations allowed are basically exhaust, reprogrammed ecu, wheels, DOT race tires, and reworked stock suspension

Formula Xtreme- up to 600cc's, almost totally unlimited modification allowed

Supersport- similar to superstock but only up to 600 cc's


The AMA passed a new rule that one team cannot compete in both Superbike and Superstock, so teams were kinda forced into devoting all their efforts into one of the classes, alot of people believe Superstock to be the future of motorcycle racing because its some of the most competitive wheel to wheel racing out there, so Kawasaki and Yamaha have put their efforts into that class, thats why you didn't see any ZX-10 or factory R1 in the race yesterday

The reason I said the rules are against Mladin this year is AMA also passed a rule that you must use a stock or similar to stock air box and throttlebody/injector set up, or you must make 200 production models with the same set-up, Honda had time to build its bike around this rule so it got dual injectors and some other stuff that allowed them a huge power advantage over the GSX-R being bottle necked in its intake and fuel delivery system, so they've had to work hard to get the most power out of what they got and further develope the handling, so theres no way you can say they will be handed the championship this year if he gets number 5 like all the runners up claimed last year... besides isn't getting on the best bike part of winning anyways