I have an older yz125 1996 i have been using castrol 2T just because wm and meijers carry it but i think i could do better. Amazon has maxima super M for 24 bucks for 64oz the castor or formula k is almost double that.Also the super M has polybutene which i heard is best. Thoughts ? I dont race just trail ride.I am going to use rotella t4 or whatever 10w40 wm or meijer has for wet clutch in the gearbox.