This update is more for bikers than anything else, but poking around the
Amsoil website I came to understand that there was a 4-stroke version of their top-of-the-line
Dominator Racing Oil brand, and wondered if indeed it might be a better choice for my vintage/WCS-custom SR500G
https://drive.google.com/open?id=0B9Nrjk17trvjQ3F5Qm9TUjRVdEVacnJCTk9qT2VOUmZKMVhjthan the
20W-50 V-Twin product that their
Signature had so thoroughly whupped on my bespoke EP Friction Test sled: it almost seems like both
Amsoil and
Mobil 1 have had to "detune" their V-Twin offerings from what one would expect for the rigors of air-cooled rear cylinder thermal duty, perhaps to favor a weak link such as the clutch in our most iconic Heavy Duty motorcycle brand.
Anyway I procured a quart ($14.00,
Auto Value special order, same day delivery)
https://drive.google.com/open?id=1iR4gUpJ8lUj5V0pRfTXOgUcOhqXoYr4Nand ran the test, which with practice has come to easily include ~100 stiction transitions (i.e., good data).
https://drive.google.com/open?id=1BPAbzQnIo1lopzDjM4MxkCw1i_ffemDfThe
Dominator edged out
Signature, as one would hope, but not by much, especially in view of the viscosity grade difference.