I am the proud owner of a 17 Roadglide Ultra, bride n I were in Wy last year on vacation, started making wierd sounds, headed home, took it to dealer, last week of factory warranty. Lifters and cam out at 18008 miles. They told me mine was the 4th on running Amsoil that had this problem. Said Amsoil was too slick, rollers on lifters skated across lobes. As I baited them further they revealed they had several others with same problem, I feel its a design problem, each lifter is now compressing TWO sets of springs, angle of rocker arms pushrods to lifter has changed as they put the cam basically in the same plane but in the center. I was so confident I bought another 3 yr warranty,, but what do I know, just an ole farm boy. I will be putting 15w60 Amsoil in this spring. BTW, McGrath HD in Coralville Iowa was the one servicing and yes they put in Amsoil as they sell it. Ride safe.