Combines belts

When you find out the problem, let me know. We lost a day because of that. The straw has been tough, hopefully that's the problem.

Not really sure about the 8780's but I have had this problem on my 750 in the past. I replaced the chopper knives and the problem went away.

We had this problem also. look in your op manual and make sure that the idler on the jackshaft and chopper are set right. If blades on chopper are good, I suspect these idler adjustments are the problem. It fixed ours. They were set wrong from the factory.