Hello - dropped the chain for the drivechain on one side of my JD 40 tiller. Able to fix the cover etc., but need to get a replacement chain. Circa 1980 I'm guessing - inherited from my late father in law. Tiller works perfectly well otherwise and would like to avoid having to purchase a new tiller. Having trouble locating a replacement chain. Any suggestions? Also, is this by chance #40 size chain that I could cut from a bulk length. Thanks.