I think there are 2 kinds of "the wrong oil". theres stuff that is just wrong and it's a known fact...wrong type, (extended milage, etc) or weight. Then theres the kind that works fine and no one really knows because no one has problems with it, and if they do it cannot be linked reliably to the oil. So the big question is how does anyone know whether it may cause the engine to wear out faster. I mean, if one guy's bike with a lesser oil lasts 100k and the other with a known good oil lasts 130k, neither is going know why thier bike went to that perticular milage before needing a rebuild. And even if 2 guys did compare considering the oils they used, it would be a rare situation. It would take a lot of people with high milage bikes comparing over a long period before any definate conclusions could be made. So what do we really know? All we REALLY know is that the wrong weight is not good, and using oil thats the wrong type for a wet clutch is not good. other than that i'd bet that till some controlled tests are done we will never truly know whether shell rotella is as good or better than mobil V twin, or whether vtwin is as good or better than mobil 1 car oil, etc etc etc.
thats why as dinqua suggests, these oil threads are pretty much useless other than to answer the already known questions like weight for example, and those take one reply before the thread is then worthy of closing.(of course even weight is subjective to a point, but beyond that point it's known)
