Originally Posted by TuefelHunden
I have survived oil threads in a multitude of forums and found no universal answer in any of them. There are some facts to consider: #1 most bikes are crashed or sold before oil plays ANY factor in your oil selection. #2 there is NOT any scientific evidence on actual wear or engine destruction published where us mere mortals can make an educated decision as to one oil being better than another. Now for a question, do you know for a fact that a particular oil (at least close to manufacturer's spec) was the absolute cause of an engine failure? Let me make that CHRYSTAL clear. Use of non-synthetic 10W40 Bluto Oil rated at SA caused a main bearing to fail due to lack of lubrication and generation of heat. This does not mean the moron didn't change oil for 250,000 miles or even checked his sight glass.
The only meaningful thing I see is that when you buy your tea kettle you should consider the fact that the transmission is going to cause more molecular shearing and the wet clutch could slip or put junk in the oil.
There's some good advice here.
You'd be hard-pressed to go on any car, truck, or motorcycle forum and find a single case of oil-related engine failure. It just doesn't happen any more. There's a small minority that keeps and uses their vehicle past 100,000 miles. There's a small minority of that small minority that does it with a motorcycle.
I've done exhaustive used oil analysis, and I've come to the conclusion that as long as you change your oil regularly and keep the level correct, you're never going to have an oil-related issue.