Neither of my Honda delaers carries the Honda GN4 in 10w-30 weight. They carry that weight only in full synthetic. The selling dealer told me they prepped the bike with GN4 10w-40. I told them the manual specifies only 10w-30. They said either 10w-30 or 10w-40 is OK. But neither the Helm or owner's manual even hints at using 10w-40 under any condition or climate. Clearly, there are more motorcycle-specific oil choices in the 10w-40 weight. Did my dealer just throw in whatever they had because they didn't want to wait to order the 10w-30? Input, please?