Sorry to start yet anothe oil thread, but the manual says either, and my temperature range (by my geographic area) falls into both ranges. The majority of my riding will be lowest temp 40 degrees - highest 95 - I live on the East coast. Which do you think I am better off using. I will be using Amsoil. Bike is ready for her 600 mile service. I have 20-50 in stock but see alot of you are usine 10-40. Before I started the oil change I thought I would consult with the higher powers. Thanks in advance.