I ride a Kawasaki 1700 that I bought new. The book specs 10W40, but I have been using 15W40 T6 in it since the second oil change. I have been reading around and found that a lot of people have been using 20W50 motorcycle oil in the 1700. Since T6 (and T4) are hard to find this year, I have been thinking about switching to 20W50. Am I going to screw anything up by making the switch? Am I going to gain anything?