Copperhead
Veteran Member
I have no doubt that Amsoil or Schaffers are good oils, but when I need a new suit I don't buy a "one size fits all", I have a taylor make one that fits exactly. i.e. Kubota oil in a Kubota.
Problem with your thinking.... Kubota doesn't make it's own oil. It is outsourced. Just like Honda brand oil... i have hauled a lot of Honda labeled oil from plant to distribution and Honda doesn't make their oil either. Same for Ford Motorcraft. Just because the OEM label is on the container doesn't mean it is the best thing going. It only means that it meets the minimum requirements and someone won the bid to make it.
And I would be willing to bet my retirement on the fact that whoever is producing Kubota's oil also produces products for a lot of other house brands. Did a little scrounging on the net and found references to Ashland as a the maker of Kubota's oils, at least the N. American variety. The same folks who make Valvoline and some other labels.