I have a 1990 1680 and my rotor belt went out on the machine this summer. It was on the machine when I bought it and had ran 2 years before it went out. In quick succession (less than a 150 acres of wheat) I went through 3 more belts. We finally put bearings and everything in the hub and it seemed to run okay after that. The spring was replaced also. I finished wheat (250 acres) and have cut about a 100 acres of milo and the rotor belt is gone again. The dealer has checked the alignment and everything else that we can think of. Is there a possibility the belts are bad or is there something else I need to check. Another customer has had issues with their rotor belts also. I bought a gates belt to put on this time. I am tired of spending $300 + for a belt each time one goes out and I sure don't need the experience of putting another one on!