Hello all, i have a 2000 426. when i first start the bike to go ride, man it rattles loudly. once it warms up it is not as loud. The thing runs great. I just added a WB e-series full pipe and rejetted the carb and it rocks. The bike still has the original tires on so i don't thing it has a lot of hours on it. The factory recomends to adjust the valves after 600 hours of riding. Should I be concerned? Once again once warm it hardly rattles at all and always run like a rocket.