Primary Tight Pulley Assy for CF 191Q 400cc 450 191R CF500AU 550cc 550 X550 ATV 0GR0-051200 This primary tight pulley assembly is designed for compatibility with CF 191Q 400cc, 450, 191R, CF500AU 550cc, 550, and X550 ATV models.It features a construction that supports under regular use.The unit provides smooth engagement and consistent performance with minimal operational noise.It is engineered to meet specifications for proper fit and function.Available in a complete range of specifications to suit various applications across ATV, dirt bike, scooter, go kart, UTV, and motorcycle systems.