Hi KK,
be careful as there were clutch pushrods with 7 mm or 8 mm diameters used !
Didn’t found out yet why and with which models, but they are existing in two versions !
What is the rod’s diameter you are looking for ?
http://www.cmsnl.com/kawasaki-1982-kz750-m1-csr-twin_model15522/partslist/6473.html#results
There should be a steel ball (part numbered as 600 in linked diagram) in the clutch assambly(?) existing.
Push rod is working against this ball and that keeps the rod from spinning with the clutch.
Cheers, Michael
