It’s no secret the Harley-Davidson owners are a loyal bunch and quite particular about how they care for their motorcycles. So it’s no surprise that some are hesitant to use anything other the house brand of Harley-Davidson Screamin’ Eagle or H-D 360 motorcycle oils. But we have been witnessing a quiet revolution in this area over the past decade as large numbers of riders are moving to AMSOIL 20W-50 or SAE 60 Synthetic Motorcycle Oils for their rides and raving about the discernible benefits of cooler operation, smoother shifting and reduced oil consumption.

How Does Harley-Davidson Oil Compare to AMSOIL Synthetic 20W-50 and SAE 60?

AMSOIL has conducted several head-to-head tests against Harley oils over the past few years. The latest comparisons show that AMSOIL delivers superior motorcycle oil.

AMSOIL 20W-50 Synthetic vs. Harley-Davidson Screamin’ Eagle 20W-50

In the chart below, we see a four-ball wear test using the ASTM D-4172B protocol. The AMSOIL 20W-50 shows a wear scar diameter of 0.40mm, while the H-D Screamin’ Eagle 20W-50 sustains a wear scar diameter of 0.59mm. The Screamin’ Eagle 20W-50 wear scar is 47.5% larger than the AMSOIL 20W-50 result. How does this affect wear control in your engine? This result proves that AMSOIL 20W-50 is vastly superior at delivering boundary lubrication protection in your engine, transmission and primary chaincase. The chance of sustaining wear damage due to metal-to-metal contact is greatly reduced. A note about the 4-ball wear test. It is a legitimate ASTM testing procedure and not to be confused with the fraudulent one-armed bandit test.

Amsoil vs. Harley-Davidson 20W-50 4-Ball Wear Test

AMSOIL SAE 60 vs. Harley-Davidson H-D 360 SAE 60 Motorcycle Oil

In the SAE 60 motorcycle oil comparison, AMSOIL SAE 60 and Harley-Davidson HD-360 SAE 60 motorcycle oils were subjected to the High-Temp/High-Shear using the ASTM D 4683 test procedure. This test demonstrates an oil’s ability to maintain viscosity protection under high temperatures. As you’ll note in the graph below, the AMSOIL SAE 60 Motorcycle Oil’s viscosity is 11.26% higher than the HD-360 SAE 60 Motorcycle Oil after the conclusion of the test. This means that the Harley oil was susceptible to shear down, while the AMSOIL SAE 60 viscosity was steadier. This translates into stable and consistent protection under extreme heat and loads.

AMSOIL SAE 60 Vs. Harley H-D 360 High Temp/High Shear Test

Which AMSOIL Product for My Harley?

AMSOIL 20W-50 Synthetic Motorcycle Oil is recommended for the following Harley Davidson applications.

AMSOIL Synthetic 20W-50 Motorcycle OilEvolution 1340 & all Twin-Cam models-

Use in engine, transmission and primary chaincase. A secondary recommendation for the transmission is AMSOIL Severe Gear 75W-110 Gear Oil.

Ironhead, Evolution Sportster and V-Rod models-

Use in engine and transmission.

AMSOIL SAE 60 Synthetic Motorcycle Oil is recommended for the following applications.

mcs-sae-60-smallFlathead, Knucklehead, Panhead and Shovelhead models-

Use in engine and transmission.