Quote:
Originally posted by ZX-12R
There are several properties of synthetic oils which are advantageous to performance oriented motorcycle engines. First is their very high breakdown temperature. Today's high revving high compression engines generate very large amounts of heat, high enough to melt the aluminum pistons if it wasn't for the fact that most modern oil delivery systems directly spray the bottom of the pistons to keep them cool. Conventional oils break down much faster in these engines resulting in sludge buildup over time. Synthetics experience almost zero buildup.
Second, synthetics film and shear strength are superior to conventional oils. This isn't so much of a problem with cars that rev to 6 or 7 thousand RPMS but with new bikes on the market having readlines upwards of 16,000 rpms, the synthetics hold up much better than conventionals under the extreme stress of a high temperature high RPM environment.
Third, conventionals have many impurities that the synthetics do not have. Because conventionals are refined from crude oil, you will never get rid of contaminants like wax, sulpher, hydrocarbons, and several other reactive chemicals. All of this crud contributes to the sludge buildup in motors. Synthetics contain far less because they are created in a controlled manner.
Another reason, not so much for a motorcycle, is cold weather starting which is a realistic concern for those of us in Western MA, Northern NY, VT, NH and ME. There is no substitute for synthetics in this case. Without friction modifiers, synthetics can be pumped efficiently in temperatures even colder than -50F while still behaving like a perfect 30 or 40 weight when warmed up. This past winter when the temps hit -30F for a few days in a row, my car started without any issues or engine noises and ran perfectly smooth (Mobil 1 5-30).
While these factors may not be an issue to someone who plans on selling their ride after a year or two, it's a worthwile consideration for those of us planning keeping the bike for years and still run it hard! Except for price, synthetic oils are superior in every way shape and form over conventionals and there is plenty of science out their to prove it.