20W-50
Most board scooters or old mopeds are two-stroke engine. This means that they mix the fuel with oil (two cycle oil). Usually the ratio is 1:20. Most four-stroke-engines mopeds have their oil cap under the seat.
4cycle
quaker state motor oil
Well on my tomos 50cc dirtbike it's 3.0 ounces of oil per U.S. gallon but that's on mine I think that should work and on my tomos it's a 50:1 fuel mix ratio
In most cases you should not mix oil into the gas of your 1979 Yamaha 50 cc moped. This type of moped had its own oil reservoir. If it is not marked on the gas You do not need to oil with the gas.
I use 15w-40 oil that's designed for (diesel engines) and it works fine! Im just using the diesel oil because its left over from my 50cc which gets REALLY hot and this oil helps keep engines nice and cool!
Mineral oil
If you buy Yamalube, it will tell you on the label what the ratio is.
Olive oil is used and some times sunflower oil can also be used.
it was either vegetable oil or olive oil
yes 2 stroke in the bottle on the handle bars and oil in the trans.