I have what is to believe a 76 SUZUKI RV 90. I don´t know much about two cycle motorcycles. The bike has been abused and I am rebuilding it. I notice a black oil fill cap on the motor next to the crank start. Is this for oil or pre mix oil for gas. We have been premixing gas because most of the electrical has been removed from the bike. I´m to is looking for a repair manual. I just purchace a owners manual on ebay. It won´t be here for 6 days.