Consumption of fuel is currently increasing, but fossil fuel reserves derived from fossils that are non-renewable are running low, to reduce dependence on petroleum, it is necessary to develop alternative renewable energy such as biodiesel. Biodiesel is a renewable fuel made from vegetable oil or animal fat. In this research, the raw materials used are biodiesel from castor oil and palm oil which are then combined with diesel oil. The purpose of study to get the characteristics of castor oil biodiesel fuel - palm oil in the form of power, specific fuel consumption, and injection process. This study uses biodiesel fuel variations in B25, B30, B35, B40 and diesel by testing physical properties. In testing using a single cylinder diesel engine which is connected to a generator with a load of 5 lamps with each lamp's 500 watt power. Then the diesel engine performance test, diesel engine performance test and injection characteristics test. The results showed that overall pure diesel fuel has a higher or more wasteful power compared to biodiesel fuel variations in B25, B30, B35, and B40. In testing the injection characteristics show that pure diesel fuel has the biggest spray angle but the shortest penetration spray. While castor oil biodiesel fuel has the longest penetration spray but has the smallest spray angle.