Combines 820 guards shake bake and forth

If you mean the entire the cutterbar, then the holddowns are too tight.

We had problems with our 1020 doing the same problem, ended up to be a broken support behind the wobble box. It is real tough to see because when not running it holds the two pieces together. I fabricated a piece of metal, took out the first guard bolts and I think two on the wobble box and bolted it down. Hope this helps.

Maybe the bar that holds guards is loose where mounted onto skid front platesIJ