Ever notice how some old wives tales refuse to die? Regardless of how much evidence exists to refute them, many seem to go on forever. One of these canards is the baseless theory that synthetic oil is so “slippery” that it causes cam roller bearings in some Harley-Davidson engines to remain stationary in the bearing race under heavy loads. Allegedly when this occurs, the cam shaft spins on the motionless rollers and scores the surface until a flat spot occurs. Purveyors of this assertion may call it roller bearing “slide”, “slip”, “float” or “skate”.

We had thought that this hogwash was proven false and forgotten years ago. We thought wrong. One of our most faithful customers (who also happens to be a journeyman auto mechanic) told us that he couldn’t use our AMSOIL Synthetic 20W-50 Motorcycle Oil in his Harley for this season. He had been told by the service manager at his Harley dealership to stay away from synthetic oil because it causes roller bearing damage. This was enough to spook our customer back to using conventional Harley Davidson brand motorcycle oil. We were very surprised that this customer was swayed by this groundless warning and wondered if this service manager had just stepped out of a time machine from 1983.

This customer had been using AMSOIL 20W-50 for several seasons and raved about how it eliminated his Harley’s oil consumption, improved his fuel economy, lowered his engine operating temperatures and improved his bike’s throttle response. AMSOIL has been declaring for years that their synthetic oil does not cause roller bearing damage and every season Harley riders log millions of very successful miles using AMSOIL synthetic 20W-50.

To get a technical repudiation of this subject, we turned to AMSOIL Technical Services.

They tell us that roller bearing damage was never due to the synthetic lubricant causing the roller bearings to “slip”. It was due to the bearings being insufficient to handle the loads. At one time Harley-Davidson used cam bearings that had 16 rollers. The 16 roller units would overload and then fatigue. Eventually the roller bearing surface would flake or pit which would cause binding and ultimately flat spotting. Harley-Davidson eventually moved to cam bearings that had 32 rollers which were better equipped to distribute loads.

When this bearing failure occurred, Harley mechanics would often point to synthetic oil as the culprit. Synthetic oils were a new concept to many Harley techs and this new-fangled oil was an easy place to pin the blame. It was easy to tell the customer that the issue was their fault for using some peculiar synthetic motorcycle oil and not Harley-Davidson engine oil. But once Harley-Davidson labelled their own synthetic oil, they had to find other reasons for these failures.

Harley-Davidson corrected their bearing design deficiency long ago, but some still believe this myth.

There are four main reasons for roller bearing failure:

1. Overloading
2. Misalignment
3. Dirt or debris contamination
4. Insufficient lubrication

Oil that is too “slippery” is not a plausible cause. Any flat-earth fears about synthetic oil should have been left in the 1970’s. We have been selling AMSOIL Synthetic 20W-50 Motorcycle Oil since 2001 and without doubt, it is our customers’ most widely acclaimed product. It is simply the most cost-effective upgrade you can make for the performance and protection of your Harley-Davidson motorcycle.

Read more about Synthetic Oil and Harley-Davidson Motorcycles

Update- January, 2018: We now sell Briggs & Stratton/AMSOIL 4T Synthetic Racing Oil in Canada. 

AMSOIL and Briggs & Stratton have teamed up to develop a state-of-the-art synthetic racing oil for 4-cycle small engines. We now offer the result of this joint venture: Briggs & Stratton/AMSOIL 4T Synthetic Racing Oil (for sale in USA only, see below for explanation). This product can be used in any four-stroke, air-cooled competition engine for karting, quarter midget and junior drag racing.

Four-Stroke Racing Engine Challenges

Briggs & Stratton/AMSOIL 4T Synthetic Racing OilExtreme Heat

Engines such as the Briggs Animal, World Formula and Raptor can wreak havoc on motor oil. These are air-cooled engines that are operated at over 10,000 rpm and depend on the engine oil to handle a considerable portion of the cooling duties. Lesser oils tend to shear down and lose viscosity under extreme heat and heavy loads. The 4T Synthetic Racing Oil formula is designed to not only withstand the extreme heat, it’s synthetic makeup will reduce heat build-up and resist viscosity breakdown. It also reduces oil loss through heat vaporization.


Briggs racing engines such as the Animal series do not utilize a pressurized oil system so they depend upon “splash” lubrication. Oil is essentially “flung” around the inside of the engine to provide oil distribution. Oil being hurled about can create air bubbles in the oil and this is known as “foaming”. The problem with foaming is that as the air bubbles are drawn into tight tolerances, they burst and leave this area prone to metal-to-metal contact. Briggs/AMSOIL 4T Racing Oil is formulated with a powerful anti-foaming additives to alleviate this risk.

Anti-Rust & Corrosion

Racing engines can sit idle for long periods between competitions and during the off-season. 4T Racing Oil is fortified with anti-corrosion additives to keep engine internals like new.

Why is Briggs/AMSOIL 4T Synthetic Racing Oil Not For Sale in Canada?

For now, this product is not being offered in Canada as AMSOIL is measuring demand to see if they can justify bilingual labeling. Until such time that they create Canadian labels, they cannot ship to Canada. If you are interested in this product, let us know and we will gladly pass this along and hopefully kick-start the process.

A synthetic racing oil developed for 4-stroke, air-cooled kart engines. Resist high heat and foaming, while maximizing horsepower output.
Brand: Briggs & Stratton
Manufacturer: AMSOIL
Model: 4T Synthetic Racing Oil
Product ID: GBS2960

Using agricultural commodities as fuel source may seem like a bright idea on the surface, but a closer look soon bears out the exact opposite. It is well established that biofuel components in either gasoline or diesel are not particularly effective. Ethanol in gasoline is a mediocre oxygenate that impairs fuel economy. It’s poor reaction with moisture can hinder performance and destroy small engines. Biodiesel congeals in cold temperatures, actually increases hydrocarbon and nitrous oxide emissions and can also cause major problems when exposed to moisture.

Functional issues aside, government biofuel programs sound warm and fuzzy, but in actual fact they pervert markets causing food prices to skyrocket and food shortages in the the Third World. Consider that HALF of the US corn crop goes directly to biofuel conversion. Biofuel subsidies motivate farmers to grow corn over other crops which certainly skews markets and normal supply patterns. These subsidies also motivate farmers to bring land into production that may have been left idle, thereby reducing wildlife habitat.

The real kicker is that is takes almost 30 percent more energy to produce of biofuels than they actually generate as fuel.

So with these considerable drawbacks, why have First World governments been so eager to promote this foolishness? Like everything related to government, look to money and power. Biofuel initiatives placate both the green and ag lobbies. These powerful groups contribute a lot of money to politicians. Politicians are also eager to deliver expensive biofuel production plants to their constituents. This despite that fact that virtually no biofuel plant in the US could even hope to remain viable without rivers of federal and state subsidies.

A new article at realclearenergy.org asks Are Biofuels Causing Food Riots? This article discusses compelling evidence to suggest that biofuel programs do indeed cause food shortages in developing nations.

Wasting food as a fuel source when their are millions starving around the world is truly one of the dumbest things we can imagine.

As any Harley-Davidson motorcycle rider can tell you, their V-twin engines can generate a lot of heat. This is especially true during slow, stop-and-go conditions. AMSOIL 20W-50 Synthetic Motorcycle Oil is designed to combat this heat and riders generally see lower operating temperatures and reduced oil consumption. But to really prove that their 20W-50 offers the ultimate in hot weather protection, they performed a test under conditions that were much hotter than could ever be experienced on the road.

In our new article AMSOIL Synthetic 20W-50 Endures Harley-Davidson Torture Test, we document how AMSOIL put a 2012 Harley-Davidson Dyna Street Bob on a dyno with no cooling fans and then ran it at intermittent speeds to replicate stop-and-go riding. They proceeded to torture the engine for close to 70 minutes with cylinder temperatures reaching over 500F. Then the AMSOIL 20W-50 Synthetic Motorcycle Oil was dropped and analyzed in the lab. As you’ll see in the final results, the oil that should have been baked could have went right back in the engine and used as though it were brand new. These vicious, otherworldly conditions barely moved the needle off of “new”.

Infrared Image of Harley Engine

Infrared image of Harley-Davidson engine during AMSOIL dyno heat test.

AMSOIL is never shy to put their products in head-to-head comparisons. In the article AMSOIL vs. Harley Davidson Motorcycle Oil, we show how the AMSOIL 20W-50 and SAE 60 Synthetic Motorcycle Oils fare against Harley Screamin’ Eagle Synthetic 20W-50 and H-D 360 SAE 60. Test procedures are used that give us an indication as to how they protect your engine under extreme conditions. When it comes to air-cooled V-twins, extreme conditions are not the exception.

AMSOIL Synthetic 20W-50 Motorcycle OilIn the 20W-50 segment, the boundary lubrication protection is measured in the 4-ball wear test. This gives us an indication as to how the oils will guard against metal-to-metal contact.

In the SAE 60 shootout, the motorcycle oils are subjected to the high temperature/high shear test. This trial demonstrates how well the oils can maintain their viscosity under extreme heat and heavy loads.