Harley Oil Debate


by Ed Newman

Featured article courtesy of American Iron Magazine

In an original article by Donny Petersen in American Iron Magazine, he defended and recommended the use of synthetic motor oils. Harley-Davidson later responded challenging his statements and recommendations. A rebuttal by Chuck Goldmann (ExxonMobil) provided readers with an excellent overview of synthetic motor oils and their advantages over petroleum. This article is the published response to all three articles. SYNTHETICS OFFER SUPERIOR PERFORMANCE AND PROTECTION

The advantages of synthetic motor oils are well known and have been written about for decades. I have SAE (Society of Automotive Engineers, Inc.) papers in my files that repeatedly endorsed the various benefits of synthetics. Whether extended service life, improved fuel economy, increased power, reduced friction and wear, resistance to breakdown, better low and high temperature protection, you name it, the documentation is out there. The studies have been done.

All of this leads one to ask a couple fundamental questions. Is the Harley V-Twin engine different from all other engines in the world? Is there something so unique with a Harley engine that all of the lubrication rules that apply to all other four stroke engines must be thrown out the window?

Yes, theirs is air-cooled and can run hot. For this reason alone one would think it even more important to have a premium synthetic motor oil.

One of Donny’s comments that bears repeating came near the conclusion of his April column. “The Motor Company didn’t reinvent the air-cooled engine and, therefore, its engines don’t require specially formulated, Harley-only fluids.” This summary remark stands at the crux of the debate.


There were two topics which the previous writers waded into with great detail which I would like to re-visit briefly here: dual qualified motor oils and additive chemistry.

Historically, one of the biggest problems AMSOIL has faced when selling motor oils to the motorcycle market has to do with this notion that automobile oils can’t be used in motorcycles. Chuck Goldmann did an excellent job of explaining how some motor oils might not be suited for both applications, but that some motor oils most certainly are. (I won’t fault him for mentioning that he personally uses a Mobil product. As you would expect, we use AMSOIL products, which Chuck knows are very good.)

There are actually two issues here. The first is that the motor oil be capable of meeting both passenger car and diesel performance requirements. The second issue has to do with the use of friction modifiers. The truth is that friction modifiers have never been a real performance issue. OEMs (bike manufacturers), however, created such a strong public perception against them that in 1998 AMSOIL re-formulated its two leading oils for the motorcycle market. Later, because of the continued misinformation that an automobile oil cannot be used as a motorcycle oil, AMSOIL took the last step of producing two grades of AMSOIL synthetic motorcycle oil.

Public perceptions and fears can drive consumer behavior, whether true or not. Last year’s Millennial Day Meltdown fear resulted in tremendous sales of generators and packaged dried foods. The fear driving this debate revolves around the question of whether it is acceptable or safe to use anything but Factory oil.


All of the articles presented chemistry lessons. I’m not sure how important many of these details are for riders, but it is fascinating for those of us who are so inclined.

Do we really need a chemistry degree in order to choose a motor oil? No. But it’s good to remember that all motor oils are not created equal.

It is unlikely that any major motor oil company today is going to produce a really bad product. But is “adequate” what riders really want? If you are going to change it frequently, if you are going to be a kind, tame rider who never gets on the throttle, well, Harley-Davidson Oil is just fine, as most motorcycle oils probably are. But if you’re the kind of rider who puts your machine through its paces, who makes modifications that bump your horsepower to the next level, if you’re cranking it up and you want to know your engine has the protection it needs, or simply want the best, a premium synthetic motorcycle oil is the lubricant of choice.

Here’s how I see it. Additive chemistries are just that: additives. They are chemicals that have been added to the base stock. These chemicals have various functions. But the final product can only be as good as the foundation you build on. Quite honestly, there would be no synthetic motor oil market if the only thing you needed to do to get premium performance from crude oil was put some chemicals in it. The fact is, petroleum has its limitations. All oils are not created equal.

A premium product does not end with the base stock. Additive selection makes a difference. Chuck Goldmann notes that not only is selection important, the process of assembling the motor oil is also important. In short, you want an experienced manufacturer who understands the interrelationship of the various components of the lubricants being produced. It is not simply a matter of putting ingredients together.

Harley-Davidson noted, correctly, that “you cannot distinguish between a good motor oil and a better motor oil by additive metals analysis alone.” Remember, though, that this is not the same as saying additive metals don’t make a difference. The truth is a manufacturer can skimp on certain chemicals to keep costs down and consumers will not notice anything, even though there are consequences. I would like to use an example from a different industry that readers may understand.

In the realm of house paint, not all paints are created equal. If you take a really cheap white paint, you may need three coats of paint to cover a medium colored surface. If you take a very high end professional paint, you can cover that surface with one coat. I once painted a black door white with a single coat of premium high quality paint. All of these paints look white inside the pail. But the high quality paint has a higher additive content. By increasing the amount of titanium white, an additive, you can get better coverage. This additive is expensive, however, and people often do not wish to pay the price, so paint manufacturers produce low end products to satisfy the consumer who wants to buy on price. Savvy consumers who value their time are willing to pay more to get the better, one-coat coverage.

When it comes to additives, AMSOIL spends more so that the oil exceeds, not simply meets, the demands of a long life lubricant. High TBN, and sufficient zinc and phosphorous, helps reduce engine corrosion and wear, increases oil service life and reduces maintenance costs.


What does all this mean for riders? There are two very real and noticeable benefits for bikers who use a premium synthetic motorcycle oil like AMSOIL. First, the engine runs cooler. Reduced friction results in cooler operating temps. If you are riding hard out on the desert or stuck in city traffic in L.A., you can definitely feel the heat from your hog. What can you do? You can’t install air conditioning. You can use a premium synthetic and run perceptibly cooler.

The second benefit, extended drain intervals and longer service life, is appreciated by many AMSOIL users. Instead of having to change the oil midway through the season, you simply change the filter. The oil’s additive package is beefy enough so that the oil is good to go for up to three times the equipment manufacturer’s recommendation or one year, whichever comes first. If you are uncomfortable with extended drains you can still change at normal intervals and needn’t have fear if inconveniences cause you to go beyond your normal oil change interval.

Another, less noticeable but very real benefit of a beefy additive package in a synthetic is this: at the end of the year, bikers in northern tier states also appreciate knowing that the anticorrosive characteristics of a premium synthetic are better than their petrol counterparts. There is less likelihood of rust and pitting on parts inside the engine as it sits idle through the winter.


A major concern many riders have had pertains to the warranty issue. Harley Davidson has created the impression that if you are a rider who uses any oil besides Harley-Davidson oil, you will void your warranty. Many motorcycle shops believe this to be the case, although the writer of the November Harley-Davidson article indicates that “in a pinch Harley-Davidson recommends that a rider use one of the API C category oils as a substitute for Harley-Davidson 360.” Nevertheless, the impression is out there that the warranty will be voided if you use another product, and since the bike has cost a good chunk of change, no one really wants to gamble with that much money on the table. Fortunately, there is a law called the Magnusson-Moss Act that says, in layman’s terms, an OEM cannot require a consumer to use an OEM part or fluid in order to maintain warranty coverage unless that part or fluid is provided free of charge.

I can’t speak for other oil companies, but I can say that AMSOIL warrants its oil against lubrication related failure. We have 28 years experience and wouldn’t be in business today if engine failures were a problem. We have more experience with synthetics and extended drain intervals than anyone in the industry.


Don, in his April column, wrote: “There is nothing wrong with Harley oil, and it is a good fossil oil to run in your bike. It is just that modern marketing can be very skillful in making the consumer paranoid about using anything but the manufacturer’s suggested oil. There are better oils out there. Period.” Right on, Donny. I can’t agree more.

It would appear that Harley-Davidson has not made it a goal to empower riders to make choices. They have made a marketing decision, forced reliance on Harley-Davidson. Is this what riders want? Do riders really want to be stuck with no options regarding motor oil selection? Do riders want to be forced to use inferior oil when they know other products can provide better protection, reduce heat, increase horsepower?

They say it is not a marketing issue, however, Harley-Davidson has chosen not to help their customers use other products. There are no factual reasons for this. Their oil does not offer the benefits of a synthetic, and it is clearly a marketing move.

A lot of riders change ignitions and make other modifications to run their Harleys at higher RPM, modifying their bikes to get more horsepower. This puts more stress on the engine, creates more heat. These modifications may also present warranty problems as well. Perhaps even a majority of riders modify their bikes to increase performance, and most really ought to be using a higher performance motor oil. It would appear that Harley-Davidson is not interested in helping these riders.

With more heat generated, oil breakdown does occur. The graph on oxidation performance in the December issue shows a shocking difference between HD 360 and Mobil 1 V Twin oil. This chart and many other tests for benchmarking performance prove emphatically the superior capabilities of synthetic motor oils. Why, then, has Harley-Davidson refused to promote the performance benefits synthetics offer? It might be that being affiliated with one oil supplier for so long has slowed Harley-Davidson’s adoption of advancements in lubrication technology.


Synthetic motor oils offer numerous performance advantages over conventional petroleum based products. For this reason, in nearly every other market – from trucks to cars to heavy duty equipment to sport vehicles – synthetics have been greeted with increasing enthusiasm. The technology is proven. The benefits are many. There seems to be no good reason why motorcycle owners should be discouraged from embracing this trend.

AMSOIL Product Information





To Place Orders by Phone

7AM-5PM Central Call Toll-Free 1-800-777-7094 Give Operator Referral # 1230864 for fastest shipping!