BACK IN THE DAY...

Here are several paragraphs from a very long article that ran in the November 1963 issue of Motorcycle Sport.

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They followed the introductory section of the article describing the lovely aroma and certain positive lubricating qualities of vegetable oil, oil from the castor bean. Castor oil used to be used extensively to lubricate racing engines. According to the article, It: “maintains a high film strength even when very hot; secondly, it has the valuable property of establishing a molecular bond with the metal that it is lubricating.”

It did, however, become a gluey mess in your crankcase or oil tank. So you drained it hot and stored it until the next race. Castor oils were not developed, as far as I know, but mineral oils certainly were, and that is the theme of the next section of the article, titled, Anti-Friction: Motor cycles could benefit from industrial developments in lubrication and bearings. It explains why we change the oil in our motorcycles as often as we do.

Additives

In the 1930s came the first of the additives to improve the performance of mineral-based oils, and by 1950 they were completely established. Some of these additives were antioxidants, designed to prevent or delay the chemical breakdown of the oil caused by heat; others increased its film strength, so that the vital layer of oil was not broken down by high bearing pressures.