My Concours 14 list 7,500 miles for oil changes, I know other brands spec the same type long (5,000, 6,000, 7,500) oil change. It does not say anything about using synthetic or mineral oil, only list the oil spec's (SJ)10W-40 recommended. Now, most of us here know that motorcycles can really chew up shear down even the best of oils. Reading most of the UOA's years past to present have shown oil's really sheared @3,000-4,000 miles. Concours 14 UOA's with SRT 15W-40 looked real beat up long before 7,500 miles. I would think that the engineers who design the engine's & tran's take all this shearing into account. Not knowing what brand of oil the owner might use that meets spec the engineers would need to account for broad range of shearing. If this is true then our motorcycles can thrive on thin oils and we really shouldn't be worrying about shearing. What do the engineers focus on that 7,5000 miles oil change interval are safe ? The way things are today I would think they error on the conservative side even @7,500 mi. Would any of you leave dino or syn. motorcycle oil in for recommended 7,500 miles knowing that it may have sheared down 20 wt. oil, even if TBN and everything else is good ?
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