Davydo - Just an fyi. My dealer suggested we run 10W-40, full synthetic 4 cycle motorcycle oil in our "wet clutch" Z800's, so I am running Mobile1 racing 4T because it is JASO certified. I believe Montana winter temperatures are a bit cooler than West Virginia's, so if 10W-40 is suggested for use by our dealers I would imagine there is no need for you to be running a 5W oil. Just my $0.02 worth. Happy riding.