I recently bought a 2003 450 sx in great condition ( so I thought), only to find out one rocker arm has been riding on the spring retainer on the intake side. The other rocker arm on the intake side has enough clearance so that it does not hit the spring retainer. Is it a common problem for the rocker arms to twist or is there something else for me to be looking for? I am already going to pull the head to see if the valve seat is worn and causing the valve stem to be higher than normal. I am also guessing the cam is probably going to be prematurely worn because of it. Since I will probably have to replace the cam, is there a cam that would be better for trail riding that I could replace it with? If you do not fully understand the thread, please do not reply.