hit this link
in quick search type in Suzuki, the alto comes up . im not sure which one is my car. my car is a 1990 RSR 660 CC
so far I think im the only one in USA that has an alto works. so we still have no clue about the car
Chassis codes to differentiate between the different models.
They all state 75W/80, API GL4 oil though so I'd go for this
I'll have a quick browse around and just make sure that is the right spec for you.