How much Lucas oil stabilizer should go in a Harley engine?

For a Harley engine, it's generally recommended to add Lucas Oil Stabilizer at a ratio of about 10-20% of the total oil capacity. For example, if your Harley engine takes 4 quarts of oil, you could add approximately 0.4 to 0.8 quarts of the stabilizer. Always consult your owner's manual or the product guidelines for specific recommendations tailored to your engine type and conditions.