The most important thing to remember is to get a motorcycle specific oil. The oil in your bike has to not only lube your crank /piston/valve train but, the clutch and gear type transmission. The wet clutch and gear transission is a unique situation not dealt with by automotive oil manufacturers.
Bel Ray is good. And if you aren't sure what to get. Just stick with any of the major manufacturers, Until you find the oil YOU swear by.
Viscosities are listed in all manuals and if you dont have it, buy it. If you can't buy it. Im sure the parts guy will look if your buying oil.
Hope that helps.