…..Starting with the 2005/2006 season, ISR racing rules dictate that the Snowcross Open Class is limited to 600cc 2-strokes, or 1050cc 4-strokes. Further, the 4-stroke rules state a 3-cylinder limit and no gear reduction. This means the Yamaha RX-1 and Apex motors are not elgible, but the Nytro/Vector engine is legal, along with the new 1050cc 2-cylinder 4-stroke from Arctic Cat!
