Terrific report, you cant ask for much better.
T5 served you well I would stick with it, I would never run the Full Syn Rotella T6 5w40 in a shared sump bike.
Your oil sheared to a 30, no big deal at all. I doubt very much you will find an oil that holds up better then yours did at 6,595 miles.
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OK I'll bite, why would you never use 5W40 in a shared sump bike?
A big air cooled twin, yea it wouldn't be my first choice, but few of those are shared sump. More manufacturers and machines are spec'ing 5W40 and several oils are up to the task. Case-in-point would be Gold Wings using the T-Syn 5w40. They are producing some of the nicest UOA's I've seen from any oil/shared sump combination and many guys have over 100K on their machines with it. I'm waiting to see how it fares in some of the new euro bikes spec'ing 5W40.
Goldwings are way easy on oil and only a tiny fraction of the bikes on the road, if you go through the motorcycle UOAs with the exception of one or two models I think you will see the other 95% of bikes that use or try Rotella 5w40 and have shared sumps, the oil shears faster and down lower then the 15w40s and 20/50s.
If its going to shear, all the 5w40 oils will always shear more then any 15w40 or 20/50 and faster. There is a reason those oils are not recommended by the manufacturers for the vast majority of motorcycles.
