M9 is actually the most desirable motor…true 8hp…early m8s had a smaller cam and crank to keep them at 5hp so 15 year olds could legally ride them…,but not there’s the larger cam and crank and everyone is making 7.9 hp motors…I have a m9 on my Eagle that re built high compression…my old crippled ass can’t kick it anymore….its headed to tenn soon for an electric start…..