Yes, that's why more & more seem to do as well or better using convential Rotella 15w-40. I just put it into mine for the heckuvit. Can't beat the price.
But that Valvoline deal sounds really good as well. I'ld try a convential diesel oil first, see how it does & use a bike oil only if you have issues w/ a couple different diesel oils. My opinion...
John.
Edit: Of course you could try T5 Rotella which is 10w-30. Have a sample of that to analyse from this summer's usage.