AMSOIL 5W-40 100% SYNTHETIC METRIC MOTORCYCLE OIL

AMSOIL 5W-40 100% Synthetic Metric Motorcycle Oil delivers premium wear protection, clean engine operation, and smooth wet-clutch performance for four-stroke metric motorcycles. Built for riders who put real miles on their Aprilia, Benelli, BMW, Can-Am, Husqvarna, and Moto Guzzi bikes, this oil handles everything the engine, transmission, and clutch can throw at it.

Metric motorcycles place unique demands on their oil. A single lubricant has to protect high-revving engine internals, lubricate transmission gears under load, and maintain proper clutch engagement without slipping or dragging. Air-cooled and liquid-cooled engines alike generate extreme heat, especially in stop-and-go traffic or on long summer rides. Many conventional and semi-synthetic motorcycle oils break down under these conditions, leading to viscosity loss, sludge buildup, and inconsistent shifting.

PREMIUM WEAR PROTECTION AT HIGH TEMPERATURES
AMSOIL 5W-40 Synthetic Metric Motorcycle Oil exceeds industry standards for high-temperature film strength. Its high-temp/high-shear viscosity measures 4.3 cP at 150°C per ASTM D4683, maintaining a durable lubricating film even under extreme thermal stress. In Four-Ball Wear Testing (ASTM D4172, 40 kg load, 150°C, 1800 rpm, 1 hour), the 5W-40 produced a wear scar of just 0.35 mm, the smallest of any viscosity in the AMSOIL Metric Motorcycle Oil lineup. A heavy dose of anti-wear additives keeps engine and transmission components protected whether you're wringing out an Aprilia RSV4 on a track day or cruising a BMW R 1250 GS across the desert.

COOL, CLEAN ENGINE OPERATION
Heat is the enemy of oil longevity, and this formulation fights it on two fronts. The synthetic base stocks resist thermal breakdown and maintain viscosity stability, with a viscosity index of 176 (ASTM D2270). That number reflects the oil's ability to hold its grade across a wide temperature range. Noack volatility testing (ASTM D5800) shows only 5.9% weight loss, meaning less oil is burned off at high temperatures. Optimized antioxidant additives prevent sludge and carbon deposit formation, keeping pistons, rings, and oil passages clean over the full drain interval.

SMOOTH, CONFIDENT SHIFTS AND LONG CLUTCH LIFE
Wet-clutch compatibility is not optional in a metric motorcycle oil. AMSOIL 5W-40 Metric Motorcycle Oil is formulated without friction modifiers, which is critical for preventing clutch slippage and glazing. It meets JASO MA/MA2 standards for wet-clutch friction performance, so shifts stay crisp and clutch engagement stays positive. Riders on Can-Am Spyders, Husqvarna adventure bikes, and BMW GS models consistently report smoother, more predictable shifting after switching from OEM-branded oils.

ADVANCED FOAM CONTROL
High-rpm riding and aggressive gear changes churn oil into foam. When foam bubbles pass between gear teeth or bearing surfaces, they collapse and leave metal-on-metal contact. AMSOIL 5W-40 Metric Motorcycle Oil scored 0/10/0 in ASTM D892 Foam Sequence I, II, and III testing, virtually eliminating foam formation across all operating temperatures. That means reliable film protection at sustained high RPM.

RUST AND CORROSION PROTECTION DURING STORAGE
Many riders park their bikes for months during winter. AMSOIL 5W-40 Metric Motorcycle Oil contains specialized anti-corrosion agents and carries a total base number (TBN) of 11.6 (ASTM D2896). That high TBN neutralizes acids that form during combustion and extended storage, protecting internal surfaces from rust and corrosion. The oil passes the ASTM D1748 Humidity Cabinet Rust Test with no rust.

SPECIFICATIONS AND COMPATIBILITY
AMSOIL 5W-40 Synthetic Metric Motorcycle Oil meets API SN and GL-1 specifications, as well as JASO MA/MA2 for wet-clutch compatibility. It is designed for use in Aprilia, Benelli, BMW, Can-Am, Husqvarna, Moto Guzzi, and other metric motorcycles that require a 5W-40 motorcycle oil. This product is not recommended for applications requiring an 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, AMSOIL 5W-40 Metric Motorcycle Oil supports up to twice the motorcycle manufacturer's recommended 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's recommended intervals. Extended drain intervals are not recommended in racing or modified engines.