Synthetic Oil for V-Twin & Harley-Davidson Motorcycles
Synthetic Protection For Air-Cooled V-Twin Engines
V-Twin engines run hot and put significant stress on oil. Air-cooled Harley-Davidson V-Twins can expose oil to extreme heat, while motorcycles that share lubricant between the engine and transmission create additional shear stress from gear operation. Lower-quality oils can lose viscosity under these conditions, reducing protection and potentially affecting shift performance.
AMSOIL Synthetic V-Twin Motorcycle Oil is formulated for high heat, cold start protection, wet-clutch performance, deposit control, and wear protection in Harley-Davidson and other V-Twin motorcycles. The Sturgis Motorcycle Rally, Daytona Bike Week, and Laconia Motorcycle Week all proudly feature AMSOIL as their Official Oil.
Not sure which V-Twin viscosity or kit fits your bike? Request a free AMSOIL catalog to explore the full range of products.
How To Choose The Right V-Twin Motorcycle Oil
SAE 20W-50 is a common choice for many air-cooled Harley-Davidson motorcycles and other V-Twins that need strong high-temperature viscosity. Choose SAE 60 for early big-bore Harley-Davidson applications that call for a heavier single-grade oil in hot conditions. Choose SAE 20W-40 for Indian and Victory motorcycles where the manufacturer recommends that viscosity, and choose 15W-60 when you want wider all-season coverage, added cold start protection, and the manufacturer approves that grade for your engine and riding conditions.
| AMSOIL V-Twin Motorcycle Oil Recommendations | |||
| Product | Best Use | Recommended Applications | Key Specs |
| AMSOIL SAE 20W-50 Synthetic V-Twin Motorcycle Oil |
Common choice for many air-cooled V-Twins, hot-weather riding, touring, and stop-and-go traffic
|
Harley-Davidson, Buell, Ducati, Aprilia, BMW, Triumph, Victory, and Indian applications
|
JASO MA/MA2, API SG/SL/CF/CG-4, ISO-L-EMA2
|
| AMSOIL SAE 60 Synthetic V-Twin Motorcycle Oil |
Heavy protection for early big-bore Harley-Davidson engines in hot conditions
|
Early Harley-Davidson applications
|
API SG, SL/CF, JASO MA/MA2, ISO-L-EMA2, API GL-1
|
| AMSOIL SAE 20W-40 Synthetic V-Twin Motorcycle Oil |
Manufacturer-specified protection for certain Indian and Victory motorcycles
|
Indian and Victory applications
|
JASO MA, API SM, ILSAC GF-4
|
| AMSOIL SAE 15W-60 Synthetic V-Twin Motorcycle Oil |
Wide-temperature service, aggressive riding, and strong cold-start protection where 15W-60 is specified
|
Indian and Victory applications, plus other V-Twins that specify 15W-60
|
JASO MA, API SM, ILSAC GF-4
|
*All trademarked names and images are the property of their respective owners and may be registered marks in some countries. No affiliation or endorsement claim, express or implied, is made by their use.
The classic air-cooled V-Twin engine found in most Harley-Davidson motorcycles gets extremely hot. For example, cylinder temperatures reached 420ºF (216ºC) in AMSOIL’S in-house dyno testing. Heat that intense wreaks havoc on cheap motor oil, causing it to lose viscosity and become thinner, effectively turning a 20W-50 into a 10W-40, or worse. Running an engine on a lighter viscosity than it is designed for increases the risk of internal engine wear.
Extreme heat also hastens chemical breakdown, as the rate of oxidation doubles for every 18ºF (10ºC) increase in oil temperature. That means for every 18ºF increase in temperature, oil life is cut in half. It’s imperative that the oil in an air-cooled V-Twin can withstand such intense heat while still delivering cold start protection. AMSOIL Synthetic V-Twin Motorcycle Oil is formulated with synthetic base oils that maintain viscosity at these extreme temperatures while supporting oxidation stability, deposit control, and cleanliness.
Bikes that use the same oil for both the engine and transmission are especially prone to viscosity loss in shared transmission compartments, as the force of shifting gears can also destroy the oil’s molecular structure. AMSOIL Synthetic V-Twin Motorcycle Oil is shear stable, helping resist viscosity loss from mechanical activity and providing reliable protection against wear under the toughest riding conditions for Harley-Davidson and other shared-sump V-Twin motorcycles.
AMSOIL Synthetic V-Twin Motorcycle Oil delivers excellent performance in the engine, transmission, and primary chaincase, offering one lubricant for all three sumps in motorcycles designed for shared use. It is available in multiple viscosities as part of our complete V-Twin product line, including complete oil-change kits with filter for Harley-Davidson motorcycles. For bikers who prefer specifically formulated oils, AMSOIL Synthetic V-Twin Transmission Fluid and Synthetic V-Twin Primary Fluid are engineered to the same exacting standards.
Specifications, Compatibility, And Service Life
AMSOIL Synthetic V-Twin Motorcycle Oils use motorcycle-specific chemistry for engines, transmissions, and primary chaincases where the manufacturer recommends that type of service. Performance specifications vary by viscosity and application, including applicable JASO, API, ILSAC, and ISO performance standards. See the individual product specifications above and always confirm the recommended viscosity and performance requirements for your motorcycle.
AMSOIL does not recommend aftermarket oil additives. Service-life guidance on the linked product pages allows drain intervals up to twice the manufacturer recommendation or one year, whichever comes first, in normal service. Always follow your motorcycle manufacturer recommendation for viscosity, application, and drain interval, and do not use dedicated transmission fluid where an API GL-4 or GL-5 gear oil is required.
Need the full product data, service details, and maintenance options in one place? Request a free AMSOIL catalog to explore the full range of products.
AMSOIL 100% Synthetic V-Twin Motorcycle Oil
AMSOIL Synthetic V-Twin Motorcycle Oil is a premium oil designed for those who demand the best protection for their motorcycles. It is the result of extensive research and is specially formulated to excel in all areas unique to motorcycles, including the high temperatures of air-cooled engines such as Harley-Davidson* V-Twins, wet-clutch performance, extreme-pressure regions of gears and chains, and rust common to short trips and storage. AMSOIL Synthetic V-Twin Oil is multi-functional and fulfills the requirements of both domestic and foreign motorcycles.
AMSOIL 20W-50 Synthetic V-Twin Oil Change Kits
Comes with specified quarts of oil, black or chrome filter, and one drain-plug O-ring
AMSOIL 100% Synthetic Transmission and Primary Chaincase OIl
AMSOIL formulated and optimized specific oils for outstanding transmission and chaincase protection
- Absolutely shear-stable
- Protects against gear and bearing wear
- Helps eliminate loud thunks and gear noise
- Helps prevent clutch slippage and glazing
- Promotes smooth shifts and acceleration
- Delivers positive clutch engagement
- Helps riders easily find neutral
AMSOIL Motorcycle Filters
AMSOIL Motorcycle Oil Filters are made from full-synthetic media and trap and hold more contaminants than other filters. They last longer, stop smaller dirt particles and offer reduced restriction for maximum engine performance and protection. Available in black or chrome.
AMSOIL Motorcycle Fuel Additives, Chain Lube, and Brake Fluid
AMSOIL General Purpose Cleaners and Protectants
From removing grease, grime, and stubborn contaminants to lubricating moving parts and defending metal surfaces against rust and corrosion, these specialized formulas make routine cleaning, maintenance, and long-term protection easier.
AMSOIL Shock Therapy® Suspension Fluids
Formulated for Fade-Free Dampening and Smooth Rebounds in High-Performance Applications
A properly functioning suspension is vital to performance during a race or maneuvering around obstacles on the trail. For greatest effectiveness, riders need a consistent suspension feel over a broad temperature range. Aggressive riding, however, can heat suspension fluid enough to cause viscosity loss, resulting in a soft, inconsistent feel. AMSOIL Shock Therapy Suspension Fluid resists viscosity loss over a broad temperature range for consistent, effective suspension feel. It reduces foaming and is engineered for riders who demand consistent, top-tier suspension performance.
To cross-reference against your current product, visit AMSOIL.com/shockfluidcrossreference.
- Controls friction and heat
- High viscosity index
- Limits shock fade amd inconsistent dampening
- Light #5, Quick rebounds under extreme temperatures
- Medium #10, More dampening & slower rebounds
- Seal conditioners for extended service life
- Race-grade technology
V-Twin Motorcycle Oil FAQ
The best viscosity is the one recommended by your motorcycle manufacturer for your engine and operating conditions. SAE 20W-50 is commonly specified for many air-cooled Harley-Davidson and other V-Twin motorcycles, while SAE 60, 20W-40, and 15W-60 serve applications that call for those grades.
Yes, if your motorcycle is designed for shared use and the manufacturer recommends that type of oil. AMSOIL Synthetic V-Twin Motorcycle Oil is designed to serve as one lubricant for all three sumps in compatible applications.
Follow your motorcycle manufacturer’s recommendation first. AMSOIL product-page guidance allows service up to twice the manufacturer interval or one year, whichever comes first, in normal service where applicable.
Yes. AMSOIL Synthetic V-Twin Motorcycle Oils are formulated for wet-clutch performance, with applicable products meeting JASO MA or JASO MA2 performance requirements. Check the specifications for your selected viscosity and motorcycle application.
AMSOIL Synthetic V-Twin Motorcycle Oil is compatible with other synthetic and conventional motor oils. Mixing can reduce the full performance benefits of the product, so a complete oil change is still the best choice when you switch.