Guys I am about to change my oil in my Yamaha Grizzly 700. I used Mobil 1 racing 4t last change a year ago and it did good. I may put 500 miles on the atv in a year so I dont know if I want to go with 10 dollar a quart oil next time. Since it is almost summer in hot Louisiana I was thinking of either Rotella 5-40 or 15-40 but couldnt make my mind up. The bike is water cooled also. Anyone have a suggestion on the two or something totally different? Thanks.