Hi and Welcome,
I don't know which bike you have, but the service manuals have setup procedures for the oil pumps. It is very important to make sure your check valves are operating properly. You will definately like the synthetics better. They are much less likely to cause problems with check valves gumming up after long periods of setting. Also you get the added pleasure of a nicer smell. Just my personal preference, Klotz works real well. Make sure you buy the oil injection version, they make others also. I personally believe it makes a better lubricant also. Good luck with your bike.
Thanks Mike