Is your slip clutch working rightIJ Are you changing the sprocket on left hand side of cylinder to speed up thresher beaterIJ Are you locking up or removing curtain over raddle chain when doing cornIJ
We had the same problem with our K years ago. Try installing the raddle cob shield---fits behind and just below the raddle chain; prevents whole and cob parts from being carried under the raddle chain and becoming pinned on the front where the chain goes around the idlers and back on top of the raddle bottom pan. Yes, very frustrating, hope this helps. Ben.