AMSOIL Metric Motorcycle Oil

If you ride a metric motorcycle, you ask a lot from your oil.

High rpm. Stop-and-go traffic. Long touring days. Hot summers. Maybe even cold spring commutes.

AMSOIL Metric Motorcycle Oil is designed specifically for that world. It is a 100% synthetic oil built for four-stroke metric sport bikes, cruisers, touring motorcycles and adventure bikes. It protects the engine, transmission and wet clutch together, so everything feels smoother and runs cleaner for longer.

The Metric line comes in four main viscosities:

• 10W-30 100% Synthetic Metric Motorcycle Oil
• 10W-40 100% Synthetic Metric Motorcycle Oil
• 15W-50 100% Synthetic Metric Motorcycle Oil
• 5W-40 100% Synthetic Metric Motorcycle Oil

Each grade targets a different style of bike, climate and riding style, but they all share the same mission: premium wear protection, smooth, confident shifts, and cool, clean performance.

AMSOIL Metric Motorcycle Oil Is Versatile

This oil is suitable for Japanese and European bikes, delivering the performance needed for both city and highway riding​

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The Four AMSOIL Metric Motorcycle Oil Grades

AMSOIL 10W-30 100% Synthetic Metric Motorcycle Oil

10W-30 Metric Motorcycle Oil is a great match for many modern metric bikes that call for lighter viscosity oil. Lighter oil can help the engine spin freely, respond faster and deliver strong fuel economy while still protecting under heavy loads.

Where 10W-30 Metric Shines

• Ideal for many sport bikes and high-revving engines that specify 10W-30
• Helps reduce friction so the engine feels lively and responsive
• Excellent cold-flow properties for cooler weather starts
• Built-in detergent package keeps small oil passages and rings clean

Riders often notice smoother shifting and quiet, relaxed engine sound with 10W-30 Metric compared to generic automotive oil. The formula is built to behave like a gear lube in terms of protection, without using extreme-pressure additives that can upset the wet clutch.

Best Use Cases For 10W-30 Metric

• High-revving inline-fours
• Commuter bikes that see a lot of city miles
• Riders chasing fuel economy and quick throttle response
• Owners who ride in moderate climates and follow the owner’s manual spec

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AMSOIL 10W-40 100% Synthetic Metric Motorcycle Oil

10W-40 Metric Motorcycle Oil is the “do-almost-everything” choice in the line. It’s one of the most popular viscosities for metric motorcycles worldwide and fits many factory recommendations.

Why 10W-40 Metric Is The All-Rounder

• Premium wear protection at both high rpm and low-speed crawling
• Smooth, confident gear changes under acceleration
• Cool, clean performance even when traffic and heat build up
• Advanced detergents help prevent deposits inside the engine

Many riders switch to AMSOIL 10W-40 Metric and immediately notice easier shifting and more consistent clutch feel. The oil is built for tough, high-temperature film strength, so even long summer rides and mountain passes do not break it down.

Best Use Cases For 10W-40 Metric

• Everyday riding in a wide range of temperatures
• Sport touring and weekend canyon rides
• Heavier bikes that still call for 10W-40
• Riders who want one viscosity they can trust all season

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AMSOIL 15W-50 100% Synthetic Metric Motorcycle Oil

15W-50 Metric Motorcycle Oil is for riders who push their bikes hard, ride in hotter climates, or own heavier touring machines that put serious heat and load into the oil.

Heavy-Duty Protection For Heat And Load

• Extra film strength to support big loads and long, hot days
• Resists thinning from mechanical shear in shared engine/gearbox sumps
• Helps engines run cooler by reducing internal friction
• Engineered to protect under highway speeds, full luggage, passengers and hills

It is especially attractive for large sport-touring bikes, adventure bikes ridden two-up with gear, and performance machines that live near the rev limiter.

Clutch And Gearbox Confidence

15W-50 Metric is wet-clutch compatible and contains no friction modifiers that cause clutch slip. It is formulated to control heat and prevent slippage and glazing, which promotes long clutch life and crisp engagement.

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AMSOIL 5W-40 100% Synthetic Metric Motorcycle Oil

5W-40 Metric Motorcycle Oil offers a wide operating range. It flows quickly at cold start, yet protects strongly once fully hot. That balance makes it a strong option for adventure riders and those who ride in changing weather.

Wide-Range Performance For Real-World Riding

• Excellent cold-start behavior helps prevent wear on cool mornings
• Strong high-temperature protection for hot days and slow traffic
• Great choice for multi-season riders in varied climates
• Wet-clutch compatible for smooth, predictable shifts

Riders with liquid-cooled twins, tall-geared adventure bikes or European metric machines often gravitate toward this grade when allowed by the manufacturer recommendations.

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Core Benefits Shared By All AMSOIL Metric Motorcycle Oils

Regardless of viscosity, the Metric Motorcycle Oil family is built around a common design goal: protect your motorcycle when conditions are at their worst, not just on easy Sunday cruises.

Premium Wear Protection And Film Strength

AMSOIL Metric Motorcycle Oil is engineered for high-temperature film strength. It clings to metal surfaces, cushions gear teeth, and guards bearings and cam lobes, even when oil temperatures soar or revs stay high for long stretches.

This strength matters because metric engines often share one oil between the crankshaft, transmission gears and wet clutch. The oil must handle all three jobs at once.

Smooth, Confident Shifting And Wet-Clutch Compatibility

A big part of the “feel” of a motorcycle is how the gearbox shifts. The Metric line is wet-clutch compatible and meets modern JASO MA/MA2 standards, helping prevent clutch slip while still allowing positive, predictable engagement.

Riders commonly report:

• Smoother, more precise shifts
• Reduced notchiness moving through the gears
• More consistent clutch take-up when hot

Cool, Clean Performance And Deposit Control

High rpm and shared gearboxes can create hot spots inside the engine. AMSOIL Metric Motorcycle Oil uses a robust synthetic base and an advanced detergent package to resist oxidation, sludge and varnish buildup.

By keeping ring lands, cam areas and oil passages cleaner, the oil helps maintain power, reduce blow-by and support long engine life.

Foam Control At High RPM

Foam is the enemy of gear sets and bearings. When foam bubbles squeeze between parts, they collapse, allowing metal-to-metal contact. Metric Motorcycle Oil uses anti-foam additives that help prevent foaming at high rpm, giving more reliable protection when you ride hard.

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Choosing The Right AMSOIL Metric Motorcycle Oil For Your Bike

Start With The Owner’s Manual

The first rule: match the viscosity and specifications recommended by your manufacturer. AMSOIL offers 10W-30, 10W-40, 15W-50 and 5W-40 Metric Motorcycle Oil to line up with common OEM requirements for metric bikes.

Then Consider Climate And Riding Style

• Cooler climates and mixed weather: 10W-30 or 5W-40 are often good fits
• Normal mixed riding: 10W-40 is the classic “do everything” choice
• Heavy touring, hot climates or loaded adventure bikes: 15W-50 can offer extra margin

If you ride aggressively, spend lots of time at higher rpm, or use your bike for long highway runs with luggage, leaning toward the heavier approved grade can provide an extra cushion of protection, as long as that grade is allowed by your manufacturer.

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Other AMSOIL Motorcycle Products That Complement Metric Motorcycle Oil

AMSOIL builds a complete ecosystem around the Metric Motorcycle Oil line. Riders often combine several of these products in the same garage so every bike gets matched fluids front to back.

AMSOIL V-Twin Motorcycle Oil Family

For American V-twin motorcycles and other bikes that do not fall into the “metric” category, AMSOIL offers a dedicated V-Twin line. These oils focus on air-cooled engines that run very hot, heavy touring loads, and the unique requirements of many V-twin clutches and gearboxes.

Even if your main bike is metric, you might have a V-twin or cruiser in the garage. Running V-Twin Motorcycle Oil in that bike and Metric Motorcycle Oil in your sport or adventure bike lets you keep brand consistency while still using the best fluid for each machine.

Primary And Transmission Fluids

Some motorcycles require separate primary and transmission fluids rather than a shared sump. AMSOIL offers fluids tailored to those systems, with the gear protection, anti-foam properties and clutch compatibility required by those designs.