Australia Karting Class. KA3 Junior (13-16 years): this class is for young people who make the step forward from the KA4 class, for the most experienced drivers who use a KA100 engine without restrictions. Power approximately 16 CV. KA3 Senior uses a KA100 engine or at the club level a Yamaha KT100S is still suitable. This class offers relatively cheap but fast and competitive rides. Power approximately 16 CV.