Comparing race cars to air cooled street motorcycles is not a good reflection on the guy who said that. As noted by Half-Crazy, race cars get the oil changed and the engines rebuilt very often, they use special purpose racing oils that are definitely not appropriate for street engines, and last time I checked there weren't any air cooled race cars still running around. Comparing apples to rutabagas.
The biggest advantage of a true synthetic IMHO is the ability to handle higher temperatures without degradation. All the other advantaqes, and there are many, are secondary when it comes to an air cooled Harley. But feel free to run dino oil if you prefer. Just make sure you change it very often and try to avoid any riding conditions that let the oil temps creep up much over 250°F. And I'm still waiting to hear what the supposed advantage is to running "regular" oil, other than possibly pricing.
By the way, I don't know what your friend was reading, but there is no reason I can think of to avoid zinc/phosphate (ZDDP) in your oil. This has been a beneficial anti-wear additive for ages, and the only controversy I'm aware of is that current emission systems with catalytic converters caused the industry to reduce the amount of ZDDP, since excessive amounts of phosphate can contaminate and kill a cat. That isn't any different for synthetic oil or dino oils, they all have to meet the same standards in this regard. And the controversy comes from those running older design engines with things like flat tappets, where the high pressure metal to metal contact can cause rapid wear of cam and tappet surfaces. ZDDP creates a boundary layer to protect the surfaces in these kinds of applications, and folks running the newer oils in those vehicles claim to have increased wear problems. This has led to marketing of ZDDP additives people can add, especially for break-in of new cams and tappets.
Jerry
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Topic: Synthetic vs. standard oil (Read 1246 times)