I have been using Mobil v-twin 20/50 since it came out. They use to make triumphs oil per Triumphs specs. I tried to buy it from them, They explained that; they were comming out with their own motorcycle oil.
Triumph has now using castrol oil. New bikes say castrol on engine.
Other than 3,000 miles each with amsoil and valvoline.Bike has about 124,00 miles on mobil 20/50 v-twin.

I was so much older then, I am younger than that now (Wrote By Dylan Sung by the BYRDS,)