Synthetic oil for Harley-Davidson motorcycle’s is probably one of the most debated subjects you will find on any message board or in any Harley magazine. I’m not about to fuel the fire about the motor companies about-face on the use of synthetics, conflicting research reports, or all the mechanics who swear that “only Harley oil is formulated for Harley engines”. Rather than writing about the merits of synthetic oil being a superior product over petrolium based products, I thought I’d simply share my own experiences and let you decide. Performance is what counts so I set out to try several brands for myself to see if there really was a difference. I’m not a chemist nor do I own a sophisticated test facility so my comparisons are based on personal observations and simple temperature readings. To read about wear test comparisons performed between Screamin’ Eagle® Synthetic (SYN3) and AMSOIL Synthetic Oil check out Amsoil vs. Harley SYN3. Also worth reading is the Great Oil Debate article written for American Iron magazine regarding synthetic oils.

Let the Tests Begin For my comparison I used a stock 2004 Heritage Twin Cam 88b with free breathing SE exhaust and K&N air cleaner. Following the initial break-in period, the recommended 1000 mile service was performed and lubricants were replaced with Harley brand petrolium based lubricants. motorcycle seat repair dorsetThe bike was driven an additional 1500 miles and monitored daily for oil temperature after the first week. motorbikes for sale 600ccAll tests were performed during the summer months on a daily commute of 40 miles under a combination of traffic conditions. motorcycle repairs cleveland qldI live in Southern California so the clutch and tranny get a good workout with plenty of time to heat up. cheap motorcycle helmets leeds

What I found was my oil temperature averaged approximately 240 degrees (Fahrenheit) at the conculsion of each commute and appeared to fluctuate approximately 7-10 degrees. Following this test (4+ weeks later) I changed oil to H-D’s Screamin’ Eagle® Syn3 20W-50 in the crankcase, primary, and transmission as recommended. Outdoor temps during this test period varied but were typically in the mid to upper 90′s. Once again I followed the same daily temperature testing and found the oil temperature dropped off an average of 2 degrees below that of the regular petrolium-based oil. Temperature readings fluctuated about the same as the conventional oil. Also the all too familiar shifting “clunk” seemed like it had quieted down slightly. On the down side, the occurance of false neutrals (or false 1st gear) increased substancially! This led me to want to try another product line just to see if it was related to the Syn3 oil or an unrelated occurance. Third Time’s a Charm! My third test was using Amsoil Synthetic 20W-50 oil in the crankcase, Amsoil synthetic 10W-40 oil in the primary chaincase, and Amsoil Severe Gear 75W-90 Synthetic Gear Lube in the transmission.

I should note here that the synthetic oils were those specified for use in V-Twin motorycles and lacked the friction modifiers as rcommended for Harley engines. I also used only genuine H-D oil filters for each test. While you can use the same 20W-50 for all 3 crankcase, primary, and transmission as with H-D Syn3 (the name Syn3 refers to use in all 3), I chose to use viscosity ranges that more closely matched those of the recommended petrolium based oils. This is probably just my own opinion but I believe 20W-50 is too heavy for the primary which requires more cooling than it does lubrication. Same goes for the transmission, where the originally equipped gear oil is closer to 75W-90 and 20W-50 seems like it would be too thin. Harley doesn’t openly publish the viscosity of their petrolium based gear oil (they just give a part number) but most agree it is in the range of 75W-90. Using 3 different lubricant viscosities also happens to be a recommendation of the manufacturer, who calls this a “Three-fluid system”.

This test using the Amsoil three-fluid system showed an average temperature reduction of 12 degrees from stock and 9 degrees less than Harley-Davidson’s Syn3. Temperature fluctuation seems to have flattened out as well with the oil temp staying between 225 and 230. Outdoor temps during the day have been a consistent 90+ degrees with quite a few days breaking the 100 mark during the testing. Things That Go Clunk in the Night Aside from cooler operating temperatures the shifting dramatically improved using the heavier 75W-90 Synthetic gear oil. That familiar “clunk” sounded slightly quieter than with the Syn3 oil… but this might have been my own perception since the shifting felt smoother. Overall I’d have to say that the Amsoil (in my opinion) is outperforming the Syn3 oil. I had thought of switching back to Syn3 to do another test, However, since the dealer charges $2 more per quart for Syn3 than what Amsoil costs, it just didn’t make sense to switch back. Slightly cooler operating temperatures, reduced noise, and cheaper price have sold me on this oil.

Though I am far from being a scientific test facility, based on my own comparision I would highly recommend Amsoil to anyone thinking of making the switch to synthetic oil. To read about wear test comparisons performed between Screamin’ Eagle® Synthetic (SYN3) and AMSOIL Synthetic Oil check out Amsoil vs. Harley SYN3. Donny Smith, contributing Tech writer for American Iron Magazine , recently described his experience using synthetic oil – Hard Driving with Synthetic Oil I’ve found the following recommendations for Amsoil lubricants for various Harley models and applications and posted them for your reference. Click Here to Request a Free Product Catalog I’ve also listed a link below of where you can purchase Amsoil online if it is not carried by a dealer near you. Amsoil Synthetic Oil OnlineThe introduction of Screamin’ Eagle® Synthetic Lubricant by Harley-Davidson® indicates the Motor Company has finally recognized the benefits of running synthetic motorcycle oil in their air-cooled engines.

After years of advising dealers and customers to avoid using synthetic oils in their bikes, it’s natural to wonder why the company is suddenly marketing one. For the past 25 years, Harley-Davidson® has claimed its petroleum-based Genuine H-D Oil is best for the “unique requirements of Harley-Davidson® air-cooled V-twin engines.” However, laboratory testing has consistently revealed that Genuine H-D Oil does not provide the best protection possible for Harley-Davidson® engines. In fact, Four-Ball Wear Tests show Harley- Davidson® 20W-50 Motorcycle Oil leaves a wear scar nearly 80 percent larger than that left by AMSOIL Synthetic 20W-50 Motorcycle Oil. Four-Ball Wear Test (ASTM D4172), 40kg pressure @ 150 degrees C, 1800 rpm for 1 hour duration The Four-Ball Wear Test is the industry’s standard test method for measuring the wear preventive characteristics of a lubricant. Placed in a bath of the test lubricant, three fixed steel balls are put into contact with a fourth ball in rotating contact at preset test conditions.

Lubricant wear protection properties are measured by comparing the average wear scars on the three fixed balls. The smaller the average wear scar, the better the protection. One of the major benefits of running a synthetic motorcycle oil is its resistance to oxidation and thermal degradation, which inhibit the formation of sludge and deposits that contribute to increased wear. In the past, Harley-Davidson® has defended use of its Genuine H-D Oil by arguing that oil breakdown in extreme heat is a non-issue because extreme heat conditions are not normally faced by motorcycle engines, while the superior cold-temperature benefits of synthetics also don’t apply to Harleys. The fact is, engine oil in Harley-Davidson® motorcycles is subject to very high temperatures. Being air-cooled, Harley-Davidson® engines get especially hot while idling in traffic, commonly reaching temperatures up to 240 degrees Fahrenheit. As heat and oxidation increase, so does viscosity, adversely affecting the lubricating qualities of the oil and increasing wear.

The water, soot and acid byproducts of combustion also contribute to deposit formation. Harley-Davidson® has stressed the importance of regular oil changes in order to remove these contaminants. Of course, promoting regular oil changes is also a good way to promote using petroleum-based Genuine H-D Oil. High-quality synthetic oils formulated with high-performance additives effectively withstand such contaminants, allowing motorcyclists to safely extend drain intervals. In support of their about-face and the introduction of a synthetic oil, Harley maintains that “the Motor Company has never supported the use of synthetic products in our vehicles because there has never been any test validations completed on the numerous formulations in HD/Buell motorcycles. This product has been exclusively designed for Harley-Davidson® and is the only synthetic product TESTED and CERTIFIED by Harley-Davidson® engineering for use in HD/Buell motorcycles.” The Great Oil Debate was an article written for American Iron magazine regarding synthetic oils and addresses the debate over using synthetic oil in your Harley.

Although it is necessary marketing hype, Harley-Davidson® V-twin air-cooled engines are not unique in their lubrication requirements and do not require a special Harley-only fluid (see letter from Harley-Davidson). There is nothing about Screamin’ Eagle® Synthetic Motorcycle Oil that sets it apart from, or makes it better than, many other synthetic motorcycle oil formulations, except that Harley-Davidson® is marketing it and directly profiting from the sales. According to Harley-Davidson®, one of the unique benefits offered by Screamin’ Eagle® Synthetic Motorcycle Oil is its versatility. For the first time the company is recommending an oil that can be used in the engines, primary chaincases and transmissions of most Harley-Davidson® motorcycles, including Evolution XL, Evolution 1340, Twin Cam 88 and 88B, Revolution and Buell models. This feature, however, is not unique. AMSOIL 20W-50 Synthetic Motorcycle Oil may also be used in the engines, primary chaincases and transmissions of these applications, providing superior lubricating protection in each component.

How does Screamin’ Eagle® Synthetic Motorcycle Oil measure up to AMSOIL in wear protection? Four-Ball Wear Test results indicate that AMSOIL Synthetic Motorcycle Oil still provides the best protection possible for motorcycles. In fact, Screamin’ Eagle® Synthetic Motorcycle Oil leaves a wear scar nearly 80 percent larger than AMSOIL 20W-50 Synthetic Motorcycle Oil. Not only does AMSOIL Synthetic Motorcycle Oil offer greater wear protection than Screamin’ Eagle® Synthetic Motorcycle Oil, it also delivers greater value. Suggested retail price of Screamin’ Eagle® is nearly $2 a quart higher than AMSOIL 20W-50 Motorcycle Oil. And because AMSOIL Synthetic Motorcycle Oil may be used for extended drain intervals of up to twice the manufacturer’s suggested interval, while Screamin’ Eagle® is recommended for standard drain intervals, AMSOIL customers realize additional savings. AMSOIL INC. has 40 years of experience providing superior lubricating protection for all brands of motorcycles, and AMSOIL Synthetic Motorcycle Oils have been tested in millions of over-the-road miles.