AMSOIL 15W-50 100% Synthetic Metric Motorcycle Oil

AMSOIL 15W-50 100% Synthetic Metric Motorcycle Oil

Precision-Formulated for Four-Stroke Metric Motorcycles

AMSOIL 15W-50 Synthetic Metric Motorcycle Oil is engineered for sport bikes, cruisers, touring, and adventure motorcycles.
It delivers exceptional protection and performance for both engines and transmissions.
Fully compatible with wet-clutch systems to ensure smooth and reliable shifting.

Superior Heat Management and Wear Reduction

Exceptional High-Temperature Film Strength

This oil exceeds industry standards for heat resistance, offering superior engine wear protection.

Robust Anti-Wear Additives

Formulated with heavy anti-wear treatments that reduce engine wear under all conditions.
Highly resistant to volatility, it prevents sludge and carbon deposits to maintain engine cleanliness.

Smooth Clutch Operation and Shift Performance

Friction Modifier-Free Formula

Contains no friction modifiers, promoting smooth clutch engagement and positive shifting.
Designed to control heat and reduce clutch slippage and glazing for extended clutch life.

Long-Lasting Clutch Protection

Supports durable clutch performance, even during aggressive riding.

Effective Foam Control for Consistent Protection

Advanced anti-foam additives help prevent oil foaming under high RPM conditions.
This ensures reliable lubrication and wear protection, enabling riders to push their motorcycles confidently.

Additional Information

Consult the product data sheet for full technical details and recommendations.

AMSOIL 15W-50 100% Synthetic Metric Motorcycle Oil

AMSOIL 15W-50 100% Synthetic Metric Motorcycle Oil is built for four-stroke metric motorcycles that work hard, ride fast and rack up miles. It’s designed for:

• Sport bikes
• Cruisers
• Touring motorcycles
• Adventure bikes

It protects both the engine and transmission and is fully wet-clutch compatible, so you get smooth, predictable shifting every ride. This oil carries a 4.9-star average rating from hundreds of riders, with reviews credited to AMSOIL.com.

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Precision-Formulated For Modern Metric Bikes

Designed Around Real Riding, Not Just Lab Numbers

15W-50 Metric Motorcycle Oil isn’t a repackaged automotive oil. It’s blended specifically for:

• High-revving four-stroke engines
• Integrated gearboxes
• Shared-sump systems with wet clutches

The viscosity range gives you easy flow when cold and a strong protective film when hot. That balance supports everything from city commuting to loaded touring in summer heat.

Compatible With Common Industry Standards

The formula is engineered to meet or exceed key motorcycle oil specifications such as JASO MA/MA2 for wet clutches and modern API service levels appropriate for motorcycle engines.

Always check your owner’s manual, but many metric bikes that call for 15W-50 or a close grade fall directly into this oil’s target range.

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Superior Heat Management And Wear Control

High-Temperature Film Strength

Sport and adventure motorcycles can run very hot:

• Fairings trap heat
• High rpm builds friction
• Slow traffic kills airflow

AMSOIL 15W-50 is built with strong high-temperature film strength. It maintains a protective layer on cams, bearings and cylinder walls, even when the oil is stressed by heat and rpm. It exceeds standard tests for film strength at high temperature, which translates into less metal-to-metal contact under load.

Heavy Anti-Wear Additive Package

To back up the synthetic base oil, the formula includes a robust anti-wear additive system. Those additives form a sacrificial layer on metal surfaces, helping protect:

• Cam lobes and followers
• Main and rod bearings
• Gear teeth in the transmission

This helps reduce wear in stop-and-go traffic, track sessions and long touring days.

Fights Sludge, Deposits And Volatility

Heat and fuel dilution tend to oxidize weaker oils. Oxidation leads to:

• Thickening
• Sludge formation
• Sticky deposits on piston rings and in ring grooves

15W-50 Metric Motorcycle Oil uses thermally stable synthetic base oils plus strong oxidation inhibitors to resist that breakdown. It’s also highly resistant to volatility, which helps reduce oil consumption and limits the formation of carbon deposits in hot zones.

Result: a cleaner engine, more stable performance and easier starting, even as miles stack up.

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Smooth Clutch Feel And Confident Shifting

Friction Modifier-Free For Wet Clutches

Many automotive oils contain friction modifiers. Those can cause motorcycle clutches to slip or glaze, especially under hard use.

AMSOIL 15W-50 Metric Motorcycle Oil is friction-modifier free and tuned for wet-clutch systems. That tuning helps:

• Prevent clutch slip under heavy throttle
• Reduce chatter and grabby engagement
• Provide a stable, predictable friction curve over the life of the oil

Riders often report more consistent clutch feel and cleaner engagement when switching from generic oils to a purpose-built motorcycle formulation.

Positive, Precise Shift Quality

Because the engine and gearbox share the same oil, transmission feel is tied directly to oil quality. With 15W-50 Metric:

• Gears see a stable, shear-resistant oil film
• Dogs and engagement surfaces stay better protected
• Shift action feels more precise and less notchy over time

The oil is engineered to reduce slippage and glazing in the clutch pack, which supports stronger launches and smoother gear changes during aggressive riding.

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Foam Control At High RPM

Why Foam Is A Problem

High rpm and gear meshing can whip oil into foam. Foam isn’t just bubbles; it is air where a solid oil film should be. That can lead to:

• Momentary loss of lubrication
• Extra wear on bearings and gears
• Instability in hydraulic lifters or tensioners

Advanced Anti-Foam Additives

This oil contains special anti-foam agents designed to keep foam in check, even at race-level rpm.

Better foam control means:

• More consistent oil pressure
• Reliable protection when you are on the throttle
• A calmer, more controlled feel from the engine and transmission at speed

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Engine Cleanliness And Corrosion Protection

Detergency For Clean Internal Components

15W-50 Metric Motorcycle Oil is formulated with strong detergents and dispersants to keep contaminants suspended and away from critical surfaces. That helps:

• Reduce varnish on pistons and rings
• Keep ring lands cleaner for better sealing
• Minimize deposits in oil passages and galleries

Clean internals mean better compression, smoother idle and a more stable power curve.

Rust And Corrosion Defense

Many bikes sit for weeks or months between rides or during winter storage. Moisture and combustion byproducts can attack internal surfaces during these periods.

This oil includes dedicated anti-rust agents and a high total base number (TBN) to buffer acids that form in the crankcase. That helps:

• Protect steel components during storage
• Reduce the risk of surface corrosion on rings and bearings
• Preserve engine cleanliness over long intervals

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Where 15W-50 Metric Really Shines

Hot Climates And Heavy Bikes

15W-50 is an excellent fit when:

• You ride in hot regions or summer desert heat
• The bike carries a lot of weight (passenger, luggage, accessories)
• You own a large-displacement, high-torque metric machine

The thicker “50” hot viscosity provides extra film strength for bearings and gears when the oil is fully hot and under stress.

Aggressive Riding And Track Days

If you enjoy:

• Spirited canyon runs
• Track days
• Repeated hard acceleration and braking

…your oil sees extreme conditions. The package of high-temperature film strength, anti-foam control and tuned clutch friction in 15W-50 supports that kind of riding. You get solid lubrication when the engine is working hardest.

Touring And Adventure Rides

Touring and adventure riders often:

• Run long days at steady rpm
• Idle through traffic in hot cities
• See dust, rain, mud and big temperature swings

AMSOIL 15W-50 provides stable viscosity across long sessions, plus extra protection against oxidation and deposits. That helps keep the engine smooth and quiet across thousands of miles.

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How 15W-50 Fits Into The AMSOIL Metric Lineup

Different Viscosities For Different Missions

AMSOIL’s Metric Motorcycle range includes multiple viscosities, such as 10W-30, 10W-40, 5W-40 and 15W-50. All are built around:

• Premium wear protection
• Smooth clutch performance
• Clean operation and foam control

Within that family, 15W-50 is the “heavy-duty, hot-running” option. It’s ideal when:

• Your manual allows 15W-50
• You ride hard in hot weather
• You want extra margin for heat and load

One Oil For Engine And Gearbox

Like the other Metric Motorcycle oils, 15W-50 is designed for integrated engine and gearbox lubrication. You do not need a separate engine oil and transmission fluid. That simplifies maintenance and keeps the friction behavior consistent across the powertrain.

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Real-World Benefits Riders Can Feel

Cooler, More Stable Running

By reducing friction and improving heat transfer, this oil helps engines run more consistently. Riders often notice:

• Less “thin, noisy” engine character when fully hot
• More stable idle after long rides
• A smoother feel through the rev range

Confidence In Clutch And Shifts

Because friction is tuned for wet clutches, riders frequently report:

• Stronger launches with less slip
• Easier gear selection
• More confidence when riding in traffic or technical sections

Several public reviews mention improvements in clutch behavior after switching to this Metric formulation.

Support For Long-Term Ownership

Cleaner internals, stable film strength and solid anti-wear chemistry all help:

• Maintain compression
• Reduce the chance of premature component wear
• Support higher resale value down the line

For riders planning to keep a bike for years, that combination is especially valuable.

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Basic Use And Maintenance Tips

Always Follow Your Owner’s Manual

Before choosing 15W-50:

• Confirm the recommended viscosity range
• Check any temperature-based charts
• Look at the required JASO and API specifications

If 15W-50 and JASO MA/MA2 are listed, this oil is an excellent match for high-load and high-heat use.

Suggested Service Habits

Most riders will:

• Follow the manufacturer’s recommended oil-change interval
• Change more frequently for racing, track use or dusty off-road work
• Use a quality motorcycle-rated oil filter

A simple pattern that works well:

• Fresh oil and filter at the start of the main riding season
• Another change mid-season or before winter storage if miles are high
• Quick visual checks of level and color before long rides

Storage And Seasonal Use

For seasonal storage:

• Change to fresh oil if the old oil has many hours
• Run the engine briefly to circulate the clean oil
• Store the bike with the crankcase full of clean, protective lubricant

The anti-rust and high-TBN package in this 15W-50 helps protect internal parts while the bike is parked.

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Summary: Heavy-Duty Protection For Metric Motorcycles

AMSOIL 15W-50 100% Synthetic Metric Motorcycle Oil is a specialized lubricant for four-stroke metric bikes that see real-world abuse:

• High heat and high rpm
• Heavy loads and long trips
• Wet-clutch transmissions and shared sumps

It delivers:

• Strong film strength at high temperature
• Robust anti-wear chemistry
• Cleanliness and deposit control
• Smooth clutch operation and confident shifting
• Foam control for steady protection

If your motorcycle calls for 15W-50 and you want an oil built specifically for metric engines and transmissions, this formulation is made to keep your bike running strong, clean and reliable mile after mile.