be sure to check what additives are, or are not in the oil...motorcycle specific oil is formulated differently than other oils..
If he was using it in an R6 he would have noticed if the clutch was slipping due to lubricant additives found in non-JASO MA oils methinks.
If that's the Rotella T6, then yeah, tons of people use it including myself. No issues, good reviews for typical usage. Heard it's not recommended for track bikes is all.