4-strokes in ISR?

With the ISR rules opening up to 4-stroke sleds, this coming year expect to see testing teams competing on Yamaha 4-stroke sleds in the Open classes. Yuji Nakazawa dominated the Japanese Snocross Series on his open mod Nytro. In the United States, Yamaha jumped into testing snocross this past season on a very limited basis. Veteran racers Jesse Strege, Trevor John and Yuji Nakazawa piloted modified Nytro sleds in North American events in 2006.