ISO 24254:2007

Overview

ISO 24254:2007 defines performance and physical/chemical requirements for four-stroke engine oils used in motorcycles, motor scooters, ATVs and related equipment where a common sump lubricates both engine and associated drivetrains (transmission, clutch, starter). The standard establishes friction-based performance classifications (EMA, EMB and EMA subcategories) and specifies key limits for properties such as sulfated ash, phosphorus content, evaporation loss (Noack) and shear stability. Friction performance is measured using the JASO T904 test procedure and expressed as three indices: Dynamic Friction Index (DFI), Static Friction Index (SFI) and Stop Time Index (STI).

Key Topics

• Scope: Oils for four-stroke spark-ignition motorcycle gasoline engines and associated drivetrains using a common sump.
• Friction-based classification: Oils are classified as EMA (higher friction), EMB (lower friction) and EMA subcategories EMA1/EMA2 based on DFI, SFI and STI ranges derived from JASO T904.
• Friction indices: Friction index calculation compares a candidate oil to two reference oils (JAFRE‑A, JAFRE‑B) to produce normalized indices for classification.
• Physical/chemical limits (examples from the standard):
  • Sulfated ash: limit specified (ISO 3987)
  • Phosphorus: defined minimum/maximum to balance gear protection vs. catalyst concerns (≈0.08–0.12 % m/m per the document)
  • Evaporation loss (Noack): maximum allowable (% m/m)
  • Foaming, shear stability and high-shear/high-temperature viscosity requirements (ASTM/CEC methods referenced)
  • Kinematic viscosity after shear for common grades (e.g., XW‑30, XW‑40, XW‑50) to ensure staying-in-grade
• Objective: Reduce misapplication of automotive oils to motorcycle applications (avoid clutch slippage, gear pitting, loss of durability).

Applications and Who Uses It

ISO 24254:2007 is practical for:

• Motorcycle and ATV OEMs specifying suitable engine oils for combined-engine/transmission systems.
• Lubricant manufacturers developing and marketing motorcycle engine oils to meet EMA/EMB classifications.
• Test laboratories performing JASO T904 friction testing and other referenced methods (ASTM, CEC, ISO).
• Aftermarket oil brands and retailers who label oils for motorcycle-specific applications.
• Fleet managers and maintenance teams selecting the correct oil to prevent clutch slippage or drivetrain wear.

Related Standards

• ISO 6743-15 (classification of four-stroke engine oils)
• JASO T904 (friction properties test for motorcycle clutches)
• Referenced test methods: ISO 3987, ISO 6247, ISO 20844, CEC L40-A93, ASTM D4683/D4741/D4951

ISO 24254:2007 helps align lubricant formulation, testing and specification with the unique friction and durability needs of modern motorcycle drivetrains - enabling clearer OEM requirements and safer, more reliable lubricant selection.