Its not the higher end, it goes out of its viscosity grade. Feel the need to mention that because we all pick on oils that go out of grade in roughly 3000 miles like so many other oils.. Just because it goes up from a 50 to 60 grade in roughly 3000 miles or less and happens to be M1 doesn't excuse it.I like the M1 VTwin 20w50 a lot, have run it in my shared sump ZRX1200 for 5,000 mile OCI's. Great additive package, not just the zinc and phosphorus but the boron and moly along with the wear numbers makes it a hard oil to overlook. As has been said here over the years, it does end up at the higher end of the viscosity range for a 20w50 in non-shared sump engines, however was right in the middle of grade in my bike after 5,000 miles.
I agree with you on that. With that said, three of the four samples above were still in grade on the high-end, only one above grade was the 4000+ mile OCI.
Looking at your tets on Mystic 15w50, it falls out a grade on the low end in each OCI I have seen posted, and I know you are very happy with the oil.
That's really what it comes down to. The oil works and engines are not having any issues.I have, if that question is to us?
2100 and 1500 miles less then a year.
Then double that mileage for 2 years.
All good, not knocking choice if oil only known facts of M1 in non shared dumps, even in motorcycle magazines some years ago. Amsoil 20/50 too. They even mentioned and I agree doesn’t seem to do any harm.
Lots of Harley riders love the oil but no denying it thickens and I think even in 6 months it would act the same in my bike as a few years and 4500 miles because it does that in other non shared Harleys.
I really cool the oil in my bike at times as you might know, however not an everyday occurrence… beach days, depends on weather and traffic