Hi! New to the group, but not to the 70´s DTs. I´ve owned a few and currently am cleaning up a new-to-me ´77 DT250. The ´77 DT250 has oil injection, which means that it is supposed to have an oil tank and oil pump. Lots of people butchered the oil system, trying to save weight and make the machine race capable. It will work fine with mixed fuel, but is certainly not stock.