I use Amsoil MCF. Other top level performers are Mobil1 Racing 4T, Maxima Ultra, Golden Spectro 4, Motul 300, and others. I don't recommend Rotella (even though it's very popular here) because it doesn't have the shear stability to be used longer than one ride day without changing. Amsoil can be bought at a local brick-and-mortar dealer for the same kind of high prices the other oil above sell for, or ordered as a preferred customer for a net cost of just under $8/qt, delivered. When the moving parts of healthy engine are properly worn in with each other, they will almost run with no oil because they're so well matched to each other. It takes very little lubrication to keep them out of trouble. This is not true of a brand new engine. In that case, the engine needs the best lubrication it can have, so why would you deliberately use less? I use the same Amsoil synthetic to break in my new engines as I run the rest of the time (I actually drain the factory oil on a new bike before the first ride). I have not ever had an engine fail to seat the rings, or have any other short or long term problem as a result. The list of high end performance cars that come factory filled with synthetic oil and require their use from day one is a long one, too. More: http://www.thumpertalk.com/forum/showthread.php?p=2685432#post2685432 http://www.amsoil.com/lit/g2156.pdf Now you got me thinking I use Rotella T in all my bikes but I do change it after every 3 rides. I have the option to get the synthetic Rotella T blue jug at Wal Mart. Do you think this has better shear properties and would be better for changing it after 3 rides instead of the white jug?