Yamalube 4, 10W-30, is recommended for a Yamaha PW80. Yamalube is the Yamaha brand of oil, and the total oil capacity is 0.75 liters on the Yamaha PW80.
The Yamaha PW80 has a two-stroke engine. There are two areas for oil on the PW80, one is the transmission and the other oil is mixed directly with the gasoline. The second area with the gasoline premix solution can be found under the seat in a plastic tank. Yamalube 4 is a 10W-30 oil, a common multi-grade oil with 10W meaning that the oil can be pumped by an engine, as well as a single grade SAE 10 oil can be. The second number, 30, correlates with the viscosity.