Biodegradable, renewable, and environmentally friendly oxygenated fuels will replace fossil fuels. A single-cylinder, four-stroke, variable compression ratio, compression ignition engine was tested for performance, combustion, emission, and vibration. Biodiesel from inedible neem, which contains 30–45% wt oil, may replace traditional liquid fuels. This work esterified and transesterified methanol and triglycerides at a 7:1 molar ratio to extract biodiesel at 96% volume.