Born from the award winning YZ competition bikes. YZ85 features a liquid-cooled. 84.7cc crankcase reed-valve-inducted six-speed that is compact and light. You also get an ultra-rigid, single backbone, semi-double-crade frame, fully adjustable suspension and more to suit a wide range of rider from novice to mini expert.
source : http://www.yamaha-motor.com/sport/products/modelhome/65/0/home.aspx