Historically, I've used Yamalube 10W-40 or 20W-50 in my 2000 Roadstar. I have friends who strongly recommend Amsoil Synthetic, which is very expensive. I all ready own 6 quarts of Castrol Actevo 10W-40 Motorcycle oil. I don't think it's synthetic, but it does say it contains "synthetic active protection molecules". Does anyone have any experience with this Castrol Actevo and would it be a good oil to use in my Roadie?