Evaluation Technique of Two-Stroke Engine Oil for Motorcycles

The main evaluation methods of two-stroke engine oil were standardized as the JASO (JASO: Japanese Automobile Standard Organization) method in 1993⁽¹⁾. After the establishment of the JASO specification, the authors executed an evaluation of various oils. As a result, it has been determined that an examination method that also evaluates the differences in demands on oil caused by regional characteristics and use conditions of the engine is necessary. Thus, the three following methods were developed. The first is a method of low-temperature detergency examination. The second is a method of low-temperature start-ability examination. The third is an exhaust port carbon blocking examination. These three examination methods are explained in full in this paper.