Yamalube motor oil.
I use 10W30 in my 1989 Yamaha Warrior.
10w-40
21/2qrts 20w50
yamalube is the best
Use 10w40 4-stroke motorcycle oil. DO NOT use any type of automotive oil; motorcycle oil is needed because of the wet clutch.
trochoid
10w30 synthetic would be my recommendation.
sae 30
winter- 5w30 summer-10w30
use good quality 2-stroke pre mix (tcw2/tcw3) tcw2 semi synthetic oil tcw3 full synthetic oil I use klotz tcw2 in my 72 Yamaha r5
You have to read the user manual and then concern your mechanic.