Modern motorcycles usually have the same oil lubricating the engine and the wet clutch. For this purpose most of the time the regular friction modified engine oils are not good enough. To make sure that the right oil is used motorcycle manufacturers usually require the oil to meet one of the JASO standards explained below.
The motor oils that meet the JASO T 903:2006 standard can be classified into four grades: JASO MA, JASO MA1, JASO MA2 and JASO MB. The classification is based on the results of the JASO T 904:2006 clutch system firction test.
In order for a motor oil to meet any of the above mentioned JASO standards it must be at least of one of the following quality levels:
API SG, SH, SJ, SL, SM
ILSAC GF-1, GF-2, GF-3
ACEA A1/B1, A3/B3, A3/B4, A5/B5, C2, C3
Furthermore, 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:
If all three properties of a JASO MA oil fall within the limits specified as MA1 then the oil can be classified as a JASO MA1 oil. If all its properties fall within the limits of MA2 then it can be classified as a JASO MA2 oil. If some properties fall within the MA1 subcategory but others in MA2 then the product is simply a JASO MA product.
Motor Oils Meeting JASO MA and JASO MB
Valvoline 4-Stroke Synthetic Motor Oil 10W-40 and 20W-50
Mobil 1 Racing 4T 10W-40
Red Line 10W-40 ester based motorcycle oil
Silkolene QUAD ATV 5W-40 Fully Synthetic 4-Stroke Engine Oil