The foaming issues with syn oil is one I haven't heard much about, I think I'll look into it more, but as far as quieting down you motor, you have to compare apples to apples. You can't compare 50W to 10-40w, or 20-50w. I'm sure if you go with a heaver weight oil it will quiet down certain noises, but I had just the opposite experience, I had an intermittent noise coming from the cam chest, dealer never did find it, or open the chest under warranty to look. I switched to Mobil1 and the noise almost disappeared, hear it once in while. But to each his own, I like the syn oils and will stick with them. I'm sure many bikes, like in the past will run thousands and thousands of miles on dino oil, just not mine.