Synthetic Oil Offers Top Performance At Higher Cost
I like using a full synthetic motorcycle oil in my 04 Harley.
Rule #1; only use an oil approved by the motor manufacturer,especially important if your motorcycle uses engine sump oil to lubricate the clutch plates.
I live in a cold climate where every one can benefit from knowledge about synthetics. The most useful quality is the high viscosity index (VI) which allows the oil to be less thin at high temperature, without thickening too much at low temperatures. This allows the oil to flow better at cold start up and it means a thicker oil film at higher temperatures, when you really need it.
Also, synthetic oils have more uniform sized base molecules, sounds fancy, but that is why synthetics are a little more slippery than refined crude oils. This results in less internal friction in the fluid, which is partially why synthetics usually run cooler than mineral based oils in motorcycle engines.
The other useful quality to the average biker is the synthetic typically has a better resistance to oxidation.
Costs more, yup, you have to balance the cost with your own idea of the value you are getting out of it, but I like my bike and I am very pleased with my choice of synthetic oil.
A good high quality filter will keep the oil clean, which keeps the engine clean. Clean oil generates fewer wear particles and it is the wear particles and contaminants which eventually degrades the oil.
Nothing like an oil change to keep the engine internals like new.