Did a search, nothing came up. Read lots of "oil" pages, none mentioned aircraft oil. At the risk of being told "We told what WE like, do what you want, it's your bike" I'll ask anyway. I know of 2 easily available synthetic blend piston aircraft oils, both less expensive than M1 V Twin syn. One is Aeroshell 15-50 and the other is Phillips XC 20-50. These are made for air cooled aircraft engines so they are made for high heat. The duty cycle of aircraft engines is typically hour after hour of 60% output or higher, no loafing down the road at relatively low percentage of output until climbing a hill or passing. Typically, we are comfortable with "overkill" when it comes to engine protection, hence the concern for the best there is for lubrication. Are there any oil experts here who can compare the formulation of the aircraft oils mentioned above with the best of the V-Twin formulations on the market, especially the anti wear additives important to Harley engines? Also, would anything in these oils disqualify them for use in the primary case?