i think the shifter kart guys run at 20-1 but they are at redline forever. im very comfy at 50-1, cylinders and pistons go past 150 hrs no sweat, never oil fouls a plug. yeah, agreed 60 to 1 in the katoom as austria recommends just feels too thin. love the motul premix, clean burn on the top of the piston and the muffler doesnt drool.