Originally Posted By: bulwnkl
Originally Posted By: Analyzer
Now, the JASO MA standard for an oils frictional properties within their test methodology provides you with three categories while maintaining JASO MA standards in this order: JASO MA, MA1, MA2...
MA is the entry level grade, followed by better/higher friction coefficients of MA1 and MA2...
You misunderstand the MA spec. MA1 and MA2 are sub-divisions of the overall MA category. The paper you linked to at jalos explains this very clearly.
I'm not exactly sure what I'm misunderstanding about the JASO MA spec, but perhaps rephrasing will help clarify everything.
The initial JASO T 903 implementation manual was published in April of 1999 with two separate grade classifications known as JASO MA and MB. The MA category was designated for oils meeting higher friction standards (dynamic, static, and stop time indexes) while MB was for the lowest friction oils for 4 stroke motorcycles (primarily many scooters and some dry clutch applications).
http://www.jalos.or.jp/onfile/pdf/4T_EV0412.pdf (pages 2 & 3)
To once again clarify, dynamic friction represents clutch feel and how power transfers through the clutch, static friction measuring resistance to clutch slippage under high torque conditions, and stop time index measuring how quickly the clutch engages.
Chemistry and Technology of Lubricants by Roy M. Mortier, Malcolm F. Fox and Stefan T. Orszulik (December 1,2009) (page 322)
JASO made an updated implementation manual in April 2006 known as JASO T 903:2006. What differentiated this revision from the original manual is additional chemical limitations, and two more separate grades: JASO MA1/MA2 and I quote, "JASO T 903, is classified into FOUR GRADES, MA, MA1, MA2, and MB, according to test results..."
http://www.jalos.or.jp/onfile/pdf/4T_EV0604.pdf (pg. 2, subsection 3.2)
As you can see on page 3 in the graph indicating the respective four different grades, JASO MB has the lowest of all friction indexes, and these friction indexes become greater and greater depending on the JASO grades, i.e, MB has the lowest, and is increased upon every successive grade to MA, to MA1, and finally MA2. Remember, "that for a lubricant marketer to claim JASO MA1 or JASO MA2, all indices must fall within the values specified for the category", i.e, if a specified oil only met two of the three tests indices of JASO MA2 and one met MA1, it would have to be labeled MA, but if it fell into all three categories of MA2 it would be labeled as such.
JASO then made another revision in May 2011 further updating friction indices between the four separate grades.
http://www.jalos.or.jp/onfile/pdf/4T_EV1105.pdf (page 3)
http://www.lubrizol.com/MCEO/Spec-Check/JASO-T903-Four-Stroke.html
I've provided a lot of references to validate what I've stated and believe it further backs up/adds emphasis to my previous post. To sum this all up, JASO T 903 has FOUR DIFFERENT GRADES of wet clutch frictional indices starting with the lowest friction rated oils and progresses to the highest in this order and stated in their previous two revisions: MB, MA, MA1, MA2. A simple search will provide a wide variety of motorcycle specific oils that meet each of these different grades, and have these variances for specific reasons. MB oils are generally more well suited to dry-clutch applications and scooters, MA is the most widely specified motorcycle oil from various manufacturers, while MA2 is widely suited for racing applications. Why might you ask? Since MA2 indexes have higher frictional properties they will provide better clutch feel and power transfers through the clutch, increased resistance to clutch slippage under high torque conditions, and more quick clutch engagement. This is why most Racing motorcycle oils like Repsol and Motul 300V meet JASO MA2 requirements, while their more "standard/economical" oils are generally rated MA. I see I've written a lot, but hopefully that clarifies everything
Originally Posted By: Analyzer
Now, the JASO MA standard for an oils frictional properties within their test methodology provides you with three categories while maintaining JASO MA standards in this order: JASO MA, MA1, MA2...
MA is the entry level grade, followed by better/higher friction coefficients of MA1 and MA2...
You misunderstand the MA spec. MA1 and MA2 are sub-divisions of the overall MA category. The paper you linked to at jalos explains this very clearly.
I'm not exactly sure what I'm misunderstanding about the JASO MA spec, but perhaps rephrasing will help clarify everything.
The initial JASO T 903 implementation manual was published in April of 1999 with two separate grade classifications known as JASO MA and MB. The MA category was designated for oils meeting higher friction standards (dynamic, static, and stop time indexes) while MB was for the lowest friction oils for 4 stroke motorcycles (primarily many scooters and some dry clutch applications).
http://www.jalos.or.jp/onfile/pdf/4T_EV0412.pdf (pages 2 & 3)
To once again clarify, dynamic friction represents clutch feel and how power transfers through the clutch, static friction measuring resistance to clutch slippage under high torque conditions, and stop time index measuring how quickly the clutch engages.
Chemistry and Technology of Lubricants by Roy M. Mortier, Malcolm F. Fox and Stefan T. Orszulik (December 1,2009) (page 322)
JASO made an updated implementation manual in April 2006 known as JASO T 903:2006. What differentiated this revision from the original manual is additional chemical limitations, and two more separate grades: JASO MA1/MA2 and I quote, "JASO T 903, is classified into FOUR GRADES, MA, MA1, MA2, and MB, according to test results..."
http://www.jalos.or.jp/onfile/pdf/4T_EV0604.pdf (pg. 2, subsection 3.2)
As you can see on page 3 in the graph indicating the respective four different grades, JASO MB has the lowest of all friction indexes, and these friction indexes become greater and greater depending on the JASO grades, i.e, MB has the lowest, and is increased upon every successive grade to MA, to MA1, and finally MA2. Remember, "that for a lubricant marketer to claim JASO MA1 or JASO MA2, all indices must fall within the values specified for the category", i.e, if a specified oil only met two of the three tests indices of JASO MA2 and one met MA1, it would have to be labeled MA, but if it fell into all three categories of MA2 it would be labeled as such.
JASO then made another revision in May 2011 further updating friction indices between the four separate grades.
http://www.jalos.or.jp/onfile/pdf/4T_EV1105.pdf (page 3)
http://www.lubrizol.com/MCEO/Spec-Check/JASO-T903-Four-Stroke.html
I've provided a lot of references to validate what I've stated and believe it further backs up/adds emphasis to my previous post. To sum this all up, JASO T 903 has FOUR DIFFERENT GRADES of wet clutch frictional indices starting with the lowest friction rated oils and progresses to the highest in this order and stated in their previous two revisions: MB, MA, MA1, MA2. A simple search will provide a wide variety of motorcycle specific oils that meet each of these different grades, and have these variances for specific reasons. MB oils are generally more well suited to dry-clutch applications and scooters, MA is the most widely specified motorcycle oil from various manufacturers, while MA2 is widely suited for racing applications. Why might you ask? Since MA2 indexes have higher frictional properties they will provide better clutch feel and power transfers through the clutch, increased resistance to clutch slippage under high torque conditions, and more quick clutch engagement. This is why most Racing motorcycle oils like Repsol and Motul 300V meet JASO MA2 requirements, while their more "standard/economical" oils are generally rated MA. I see I've written a lot, but hopefully that clarifies everything