AMSOIL 10W-40 100% SYNTHETIC METRIC MOTORCYCLE OIL

AMSOIL 10W-40 100% Synthetic Metric Motorcycle Oil delivers premium wear protection, clean engine performance, and smooth wet-clutch engagement for four-stroke metric motorcycles. Built for sport bikes, cruisers, touring machines, and adventure bikes from BMW, Honda, Kawasaki, Suzuki, Yamaha, Can-Am, and Triumph, this is a purpose-built motorcycle oil that handles the unique demands of shared engine and transmission lubrication.

Metric motorcycles put their oil through a punishing cycle. The same lubricant protecting high-revving engine internals also has to flow through the transmission gears and manage wet-clutch friction. That means the oil has to resist shearing under mechanical stress, stay thermally stable at sustained high RPM, and do all of it without the friction modifiers found in automotive oils that cause clutch slippage. A general-purpose 10W-40 motor oil is simply the wrong tool for this job.

PREMIUM WEAR PROTECTION AT HIGH TEMPERATURES
AMSOIL 10W-40 Synthetic Metric Motorcycle Oil exceeds industry standards for high-temperature film strength. With a high-temperature/high-shear (HTHS) viscosity of 4.7 cP at 150°C (ASTM D4683), this oil maintains a durable protective film between metal surfaces even under extreme thermal loads. In Four-Ball Wear testing (ASTM D4172, 40 kg load, 150°C, 1800 rpm, 1 hour), the 10W-40 produced a wear scar of just 0.37 mm. A heavy treatment of anti-wear additives provides consistent protection whether you're stuck in stop-and-go traffic on a Honda CB650R or running sustained highway speeds on a Yamaha Tracer 9 GT.

WET-CLUTCH COMPATIBLE FOR SMOOTH, POSITIVE SHIFTS
This oil contains zero friction modifiers. That is critical for any motorcycle with a wet clutch, which includes the vast majority of metric bikes on the road. Friction modifiers reduce drag in automotive engines but cause clutch slippage and glazing in motorcycles. AMSOIL Synthetic Metric Motorcycle Oil meets JASO MA/MA2 standards, providing the friction characteristics wet clutches need for positive engagement and long clutch life. Riders on Kawasaki Z900s, Suzuki GSX-S1000s, BMW F 900 Rs, and similar machines will notice clean, confident shifts from day one.

THERMAL STABILITY AND ENGINE CLEANLINESS
Air-cooled and liquid-cooled metric engines alike can push oil temperatures well past the range where conventional oils break down. AMSOIL 10W-40 Metric Motorcycle Oil resists volatility with a Noack Volatility result of just 7.2% weight loss (ASTM D5800), meaning less oil consumption and less deposit-forming vapor cycling through the engine. A flash point of 230°C (446°F) and fire point of 240°C (464°F) reflect the thermal resilience of the synthetic base stock. Optimized antioxidant additives resist sludge and carbon deposit formation, keeping critical engine components clean and maintaining performance over the full drain interval.

CONTROLS FOAM UNDER HIGH-RPM OPERATION
Motorcycle engines routinely spin past 10,000 RPM. At those speeds, oil aeration and foaming become real concerns because foam bubbles collapse under load and allow metal-to-metal contact. AMSOIL 10W-40 Metric Motorcycle Oil recorded foam values of 0/20/0 across Sequence I, II, and III testing (ASTM D892). Advanced anti-foam additives keep the oil stable so wear protection remains consistent even when the tachometer is pinned.

SUPERIOR RUST AND CORROSION PROTECTION FOR STORAGE
Many motorcycles sit for weeks or months between rides, especially in colder climates. AMSOIL Synthetic Metric Motorcycle Oil contains dedicated anti-corrosion agents and passes the ASTM D1748 Humidity Cabinet Rust Test with no rust. A total base number (TBN) of 11.6 (ASTM D2896) provides strong acid-neutralization capacity, protecting internal engine surfaces from corrosive byproducts during extended storage and long periods of inactivity.

SPECIFICATIONS AND COMPATIBILITY
AMSOIL 10W-40 Synthetic Metric Motorcycle Oil meets API SN and GL-1 specifications and is JASO MA/MA2 certified. It is designed for BMW, Can-Am, Honda, Kawasaki, Suzuki, Triumph, Yamaha, and other metric motorcycles requiring a 10W-40 motorcycle oil. This product is not recommended for applications requiring API GL-4 or GL-5 gear oil. It is Warranty Secure and will not void your motorcycle's factory warranty.

SERVICE LIFE
When paired with an AMSOIL Oil Filter, this oil is good for up to twice the motorcycle manufacturer's recommended oil change interval (miles or hours) or one year, whichever comes first. When using any other oil filter, change the oil and filter at the manufacturer-recommended intervals. Extended drain intervals are not recommended in racing or modified engines, where oil changes are at the owner's discretion.