Quantity: 4 × 1-Quart Bottles (Total: 4 Quarts). Red Line 20W‑50 Motorcycle Oil is a fully synthetic, ester-based formula developed for high-performance motorcycles. Whether you're riding a Harley-Davidson V-Twin or another air-cooled engine under tough conditions, this oil provides the film strength, heat resistance, and anti-wear protection your engine and clutch demand.