In the sport of motorcycle racing, where participants reach speeds in excess of 300km/hour, it can be expected that they exhibit different personality characteristics and behaviour to participants in other less extreme types of sports. This study examined the relationship between the theoretical constructs of serious leisure, flow state, sensation seeking personality and the sport motivations of motorcycle riders in Australia using a mixed method approach. The study findings include a comprehensive review of the motivations why individuals engage in the sport of motorcycle racing in Australia reflecting a critique of literature from a diverse range of sources. Secondly, a range of motivational theories have been applied to the extreme sport of motorcycle racing offering a new insight into the sport. Thirdly, the main personality traits that are critical to explaining why individuals sustain their involvement as a motorcycle road racer in Australia have been identified. Study results revealed that it is the level of intrinsic motivation experienced that keeps the riders returning to such an extreme sport, even if injured, as racing is what each individual freely seeks to do.