"Perhaps this is the article you are remembering incorrectly?
Motorcycle Consumer News: Motorcycle Oils vs. Automotive Oils"
No, it was the two part article ""MCN Oil Investigation Update" published in January and February, 2003. Quoting from the section Are Bike and Car Oils Really Different MCN reports: "As you can see in the charts there are a lot of similarities. Mobil adds magnesium to the MX4T product that is not present in the Mobil 1 car oils. We can also see from the viscosity and heat aging data that the Mobil uses a different base stock between the the bike and car oils. At least in Mobil's case the claim that motorcycle oils is "different" can be substantiated, as it contains a heavier-duty additive package. However, their automotive oil still posts a higher TBN than their bike oil, while costing nearly half as much."
(TBN is total base #, a measure of the oil's ability to counteract crankcase acids)
There was also a few sentences about many of the automobile oils containing > 1000 ppm levels of phosphorus. This is a source of phosphoric acid, which one does not want in an engine.
MCN goes on to say in the Conclusions section. ""While motor oil is perhaps the most complicated of all the products we evaluate ... . We also want to present data that can help you decide which product to use in your bike, based on the way you ride."
I'm glad you get good results with automobile oil. To me, the small additional cost/year to use motorcycle-specific oil is a worth-while investment in peace-of-mind.
After rereading our posts I think the most important thing we both said is to change the oil regularly and often.
