For a Mobile 1 product, I would use their Mobile 1 Racing 4T Motorcycle Oil. I think "Racing" in the name is kind of a misnomer, in regards to street use anyway.
For my 1981 KZ650-CSR, I have used Shell Rotella T 15W-40 regular in the white bottle. It has the Japanese JASO-MA rating. I also use Chevron Delo as it's also a heavy duty engine oil marketed for diesel engine use & both usually go on sale at various places.
1981 KZ650-CSR. Competition, Sports & Road.