BS ISO 24254:2007

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Four-stroke cycle engine oil requirements
Annex A (informative) - Background and examples of
                        assignment of performance
                        classification
Bibliography

Describes the requirements of lubricating engine oils (hereinafter referred to as "four-stroke engine oils") to be used in four-stroke cycle spark ignition gasoline engines employing a common sump containing the lubricating oil for both the engine and associated drivetrain (transmission, clutch, starter) of motorcycles, motor scooters, all-terrain vehicles (ATVs) and related equipment.

This International Standard specifies the requirements of lubricating engine oils (hereinafter referred to as “four-stroke engine oils”) to be used in four-stroke cycle spark ignition gasoline engines employing a common sump containing the lubricating oil for both the engine and associated drivetrain (transmission, clutch, starter) of motorcycles, motor scooters, all-terrain vehicles (ATVs) and related equipment. Classification of four-stroke engine oils is defined in ISO6743-15^[1]. Among all of the categories covered by ISO6743-15, this International Standard includes categories EMA and EMB.

This International Standard specifies the performance classification of four-stroke cycle gasoline engine oils based on physical and chemical properties, and three friction performance indices, which are derived from the frictional properties of the lubricant, according to the JASO T904 test procedure¹⁾.

NOTE For the purposes of this International Standard, the term “%(m/m)” is used to represent the mass fraction.