Choosing the right motorcycle oil: Understanding JASO grading system

In 1998, Japanese Automotive Standards Organization (or JASO for short), an organisation that sets automotive standards in Japan, developed a grading system for motorcycle oils. This standard is analogous to the Society of Automotive Engineers (SAE) in the United States.

The grading system measured (amongst other things) an oils ability to resist clutch friction (or slippage), protection offered against engine wear and pitting in the gear box.

Up to 1998 car oils had been used as the base for many motorcycle oils. As car technology evolved over the years the oils that cars needed changed and additives were added that weren’t good for motorcycle engines (especially motorbike clutches and gearboxes, mainly due to the fact that, unlike most motorcycles, cars use a separate oil for the gearbox). Car oils had been blended using more and more friction modifiers, which, although good for cars, wasn’t not suitable for use in motorcycles as these modifiers can cause clutches to slip at higher revs and gearbox pitting.

JASO introduced 2 ratings for 4 stroke motorcycle oils:

JASO MA – This was the standard for single unit engines where the wet clutch, gearbox and engine used the same oil. JASO-MA oils don’t contain friction modifiers.

JASO MB – This lower standard was for bikes that use separate oils for the engine, clutch and gearbox (e.g Harley Davidson’s and BMW’s).

In 2006, JASO introduced:

JASO MA2 – This specification was introduced in 2006 for modern motorcycle engines. As well as being a higher standard of oil the JASO-MA2 approval means the oil is suitable for use in bikes with catalytic converts in the exhaust system.

To make sure that the right oil is used, motorcycle manufacturers usually require the oil to meet one of the JASO standards explained above and the motor oil’s Dynamic Friction Characteristic Index (DFI), Static Friction Characteristic Index (SFI) and Stop Time Index (STI) should be within the following limits according to the JASO 904:2006 friction test:

Source: JALOS (Japan Lubricating Oil Society)

JASO also introduced a rating system for 2 stroke motorcycle oils. Modern 2 stroke motorcycle and scooter engines have much finer tolerances and low ash burn (which means less smoke) and need a higher specification 2T oil.

JASO FA – Original specification established regulating lubricity, detergency, initial torque, exhaust smoke and exhaust system blocking.

JASO FB – Increased lubricity, detergency, exhaust smoke and exhaust system blocking requirements over FA.

JASO FC – This specification has the same level of tests as JASO-FB for lubricating capability and initial torque. But it has much higher standards for detergents and exhaust smoke.

JASO FD – This specification is almost the same as the JASO-FC specification but with much higher detergent capabilities.

Where to find the JASO information on an oil bottle…..

For 4 stroke:

For 2 stroke:

Here are motorcycle oils that meet MA/MA2 and MB in TOTACHI and DENTO series.

 

4T JASO MA Motorcycle Oils are available in both

Totachi Signature series and DENTO series.

4T JASO MB Motorcycle Oils are available in

Totachi DENTO PAWA Matic 4T series.

For more enquiries on our product selection, please consult our distributors in your country or email us at info@totachi.com for assistance.