Worn helicals will sure add to the problem. You should be able to just reach around the cage and feel them. like has been said before you dont need very many reverse basr, if any at all. The triangle and helical over the corner of the rear feed chain will also hellp in most conditions. like Dan said, my fist thought is "your problem isnt cleaning, it is not making tiny pieces of straw". Just like in the past when people claimed they had problems with cage sweeps.....if you had problems with cage sweeps plugging......cage sweeps werent your problem, you needed to keep some straw in the cage. Van