Overview

JASO MA oils deliver higher level clutch frictional performance. They are formulated for use in four-stroke motorcycles and scooters and are primarily suitable for wet-clutch applications. Oils which meet JASO MA performance requirements, can also be sub-categorised into meeting MA2 (higher clutch friction) or MA1 (lower clutch friction) performance.

The main physical, chemical and clutch frictional requirements, according to the current version of the standard (JASO T903:2016), for JASO MA oils are shown below:

Physical and Chemical

Requirement Methods Unit Limit
Sulphated Ash D874/JIS K 2272 % mass 1.2 max.
Phosphorus D4951/JPI-5S-38 % mass ≥0.08 and ≤0.12
Molybdenum D4951/JPI-5S-38 ppm Report
Foaming Tendency
  Sequence I  

D892/JIS K 2518

mL 10/0 max.
  Sequence II mL 50/0 max.
  Sequence III mL 10/0 max.
Evaporation Loss (NOACK) D5800/JPI-5S-41 % mass 20 max.
Shear Stability

(Kinematic viscosity (100°C) after test)

ASTM D62781) mm2 xW-30 : 9.0 min.

xW-40 : 12.0 min.

xW-50 : 15.0 min.

Others : Stay in grade

High Temperature High Shear (HTHS) viscosity D4683/JPI-5S-36 mPas 2.9 min.

Note 1) : Test shall be conducted by diesel injector method using the standard test conditions (30 cycles)

Clutch Test Friction Properties (JASO T 903:2016(Annex A))

Property JASO MA
Dynamic Friction Index (DFI) ≥1.35 and ≤2.50
Static Friction Index (SFI) ≥1.45 and ≤2.50
Stop Time Index (STI) ≥1.40 and ≤2.50

Note : MA, MA2 and MA1 shall be within the respective ranges described in the table above for each of the three indices (DFI, SFI, and STI).

Submitter may On-File register an oil which satisfies the MA specifications as a MA, MA1 or MA2 oil depending on the indices specified and marketing requirements.

The significance of the indices:

Dynamic Friction Index (DFI) Measure of clutch feel and how progressively power transfers during clutch engagement
Static Friction Index (SFI) Measure of closed clutch pack torque handling capacity – resistance to clutch slip under high-torque “break-away” conditions
Stop Time Index (STI) Measure of how quickly the clutch engages