Dawg...Looks like we've both got friends with different information...no doubt, HD syn is not produced by anyone we want to do business with!! My friend distributes Mobil 1 products, so naturally, he's a little biased, but he also says that Amsoil is an excellent product, and like I said in an earlier post, I don't think you could go wrong using their oil, as it is right there in the top 4 or 5, along with Mobil 1, according to my friend. I think the guys pretty up front to even say that. Motul is another one he recommended in countries where Amsoil or Mobil is not available. BUT, Mobil 1 20w50 VTWIN was specially formulated by a dude who owns Harleys and other vtwins for optimum performance and wear characteristics. Not to say that heavier oil in the other holes is going to hurt anything at all, but it's harder to "churn", and friction robs HP, that's all. Like I said, if it works, keep on doing it. Just trying to post information that might be of some value and it definitely made me think outside my normal "box" and change my ideas about some things. One things for sure, I won't be using HD syn3! At least not after the intitial change.