Just saw you live in NM. During the real hot months I wouldn't run anything under 10-40. I'm moving to pheonix and in the summer I will run 15, a little thicker and doesn't heat up as fast in 100 degree weather. The 5 would heat up real quick, that's good for in the winter, or the 10 like you have now. The R-4 is spendy, but I work at a shop so I get it for cost, which is still more than your mobil, but I save enough on the other stuff so it doesn't matter. Is the mobil made for motorcycles? Any other questions you have I can ask my boss who's been working on bikes for 30 years, so he pretty much know's everything.