ASK THE MXPERTS: A QUESTION ABOUT THE KTM 350SXF, KTM 250SXF AND THE 450 CLASS

    However, if you look closely at the AMA Supercross rulebook you will discover that the displacement allowed in the 450 class is 249cc to 450cc. That two cubic centimeter difference means that a 250cc four-stroke can race in 450 Supercross, but not the 450 Nationals.

   Why does Supercross allow 250Fs in the 450 class? First and foremost?because they can. They are mostly “show” producers and don’t care about the traditions, rules or reasons for why any rule was written. They care about the show. And the show can get into trouble. For example, Supercross often runs into a problem with getting enough big-bike riders have have a full gate for its two 20-man 450 heat races. Thus, the Supercross promoter’s juggled the AMA rule book as a way to avoid the embarrassment of not having enough riders on the starting line. By lowering the displacement from 251cc to 249cc, when the promoters come up short on 450 riders, they can legally get 250 East/West riders to ride in the 450 class (without the riders having to have a 450cc machine). In the past they have even bribed 250 riders to move up to the 450 class for the night by paying them a bonus…although most of these riders raced both the 250 and 450 classes (which is also illegal under AMA National rules).

   Allowing 250F’s in the 450 class is a stupid rule because the power difference over the doubles and triples in Supercross often sees the 450 riders jump over the 250 riders. This is dangerous, especially if a 450 rider comes up on a slower 250?and fully expecting him to jump, the smaller bike comes up short.

    Most organizations, including the AMA in the past, raise the lower limit of the displacement to keep riders from using smaller engines in big-bore classes. For example, in the 450 FIM World Championship the four-stroke displacement limits are 290cc to 450cc.