Air-cooled V-twin engines as used in Harley-Davidson motorcycles are prone to very hot operating temperatures. Things can get especially toasty during periods of extended idling or when caught in slow moving traffic. With this tendency in mind, AMSOIL decided to make a point regarding their AMSOIL 20W-50 Synthetic Motorcycle Oil and it’s ability to withstand severe heat.

The Heat/Dyno Torture Test

AMSOIL installed their Synthetic 20W-50 in a 2012 Harley-Davidson FXDB Dyna Street Bob and placed it on a dynomometer. Then they ran it at varying engine speeds from idle to slow speed and then rolled on the throttle to replicate city driving conditions. The electronic high-temperature safety sensors were disconnected to keep the engine from shutting down as the engine temps reached critical levels. With the dead air of a dyno room, the only two things that would contribute to cooling the engine were the cylinder fins and the engine oil. The test went on for almost 70 minutes with cylinder temperatures topping out at over 500F! These are temps well beyond what would ever be experienced under real world conditions.

Anyone who has ever idled a Harley on a hot day while waiting for a long train to pass, can attest to how this demo would be a considerable test of engine and oil.

Infrared Image of Harley Engine

Infrared image of the Harley Twin Cam 96 engine during dynomometer heat testing with the heat scale shown on the right. Note the back cylinder reaching 530.4F!

The Results

Upon completion of the test, the engine oil was drained and whisked off to the lab for analysis. The results were quite astonishing. Engine temperatures that should have seized the engine solid and completely destroyed the oil, barely changed the oil properties from what they looked like out of the bottle. The viscosity did not change at all. Only mild oxidation occurred. The “TBN” or total base number (the oil’s capacity to combat acidity) was hardly affected. Lastly the engine did not experience accelerated wear during this extraordinary trial as wear-metal findings were negligible. To sum up these results, one could accurately suggest that this batch of AMSOIL 20W-50 Synthetic Motorcycle Oil was barely broken in and would be more than suitable for continued use for a full season.

Harley-Davidson/AMSOIL 20W-50 Heat Test Results


AMSOIL Synthetic 20W-50 Motorcycle OilConclusion- Is Conventional Oil Good Enough for your Harley?

One can conclude from these results that you can take your Harley to hell and back and AMSOIL 20W-50 Synthetic Motorcycle Oil will protect your engine and come back for more. Do you still believe that synthetics are not worth the few extra bucks in Harley-Davidson motorcycles? This test and the real-world performance upgrade that our customers rave about would suggest otherwise.

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