This guide will show you how to change the oil in the transmission of the Evolution motor of the Harley-Davidson Sportster. The Evolution Sportsters have wet clutch and primary drives. It is recommended to change the oil at 1,000 miles, then every 10,000 miles after that. The manufacturer recommends using 20w50 oil. The downside to this is, they run hot. When tuned properly, the oil should not go above 240*F, even in the worst of conditions. I have 2 v-twins, one is a TC. It's a 117" motor, at near 11:1 static compression and tuned. The oil on the hottest summer days has never been north of 235*F. Normally it's 210*F.