Do additives (Zinc, Phos and Moly) make motorcycle oils more expensive?
• Yes and no. • Zinc, Phos, and Moly are extreme pressure additives. They “activate” at different temperatures, so the combination gives you protection at all normal operating temperatures. Calcium (and likely magnesium as an “impurity”) are in there as carbonates to neutralize acids formed during combustion (Richard, certain forms of calcium carbonate, I.e. platelets, can also double as a quasi-EP additive). Boron is part of a borate compound, but I have forgotten it’s purpose (rust & oxidation inhibitor?). Silicon can be a sign of poor air filtration (dust is silicon dioxide), or from the defoamer used in the oil (usually silicone/siloxane), or as part of an aluminum alloy (usually 5-10% in pistons). Most of the other metals are wear bits from the engine…tin, lead and silver tend to come from bearings, chrome and nickel from chrome plated items (piston rings?), copper from bearing cages. As was said, the good things tend to go down in concentration, the wear things tend to go up (i