Japanese Automobile Standards Organization (JASO)

The Japanese Automobile Standards Organization (JASO) is an industry organization and specification setting body for lubricants designated for use in a broad range of Japanese hardware. JASO small engine specifications are broadly recognized and have been adopted globally by the industry as key performance standards for both 2-stroke and 4 stroke applications. The JASO standards are used by oil marketers and many OEMs globally as an indication of the baseline performance upon which their performance requirements are built. The JASO emblem and associated specifications displayed on oil containers assist consumers with identifying the correct lubricants for motorcycles and other small engine equipment.

For 4-Stroke applications, JASO introduced the T903 specification in 1998 as a global standard. The specification was designed to address clutch slippage problems in the field, provide the correct balance between hardware durability and catalyst protection and to improve fuel economy performance in scooter applications.  This was in direct response to industry concerns relating to the incorrect use of lower viscosity and highly friction modified lubricants in wet-clutch motorcycle applications and a need to upgrade the quality of four-cycle motorcycle lubricants available in the market.

For 2-Stroke applications, JASO introduced the M345 specification in 1994 as a global standard. The specification was designed to set a minimum level of engine protection and exhaust emissions control performance, in response to industry concerns about the durability of two-cycle engines and quality of two-cycle lubricants available in the market.

For a deeper dive into specifications, see the Lubrizol Ready Reference Guide, the industry's go-to resource for understanding fuel and lubricant performance principles and requirements.