.... just an observation. I put Royal Purple in the lady after using Rotella T, Mobil oil, Honda oil, Amsoil, and I have found in this East Tennessee weather, hot as hell, their 10w40 is UNBELIEVABLE! I change the oil yesterday took it out for a short ride due to the 4th traffic, not much difference. Today in the hot of the day, 93 in Sevierville, Tenn. the fan didn't come on as much, and with the radio off I actually heard the turn signal clicking. This is something I've never heard ever since I bought the wing. The shifting both up and down are a lot smoother, and if you are just right on the shifting, clutch/gear change, it's almost like an automatic. That part is hard to explain it's just different. The bike is a lot quieter, as I said. $18+ dollars a quart might be a little steep, but the "extended" oil change may make a difference. But, hey, it's the lady... and she is worth it! Right??