Can somebody elaborate on the differences in the engines? I know there is something with the exhaust cam, the displacement is different. Is it the bore or stroke that is different? What is it that gives the bike engine the 7-9hp advantage? I know the number varies on who you talk to, but I know it is a fair amount. I won the bike, and a friend has the quad, and we're curious as to what exactly the differences are. In detail preferably. Thanks!