Originally Posted by Brian553
SonOfJoe did mention in post #5094916 :
it's no stamp of approval, and is most likely only MA1, but is a tiny keyhole to where PCMOs stand in terms of wet clutch performance. Better than no keyhole.
Originally Posted by SonofJoe
The memory's beginning to fade now but as I recall, most of the Euro 10W30 PCMOs I formulated (even the lowly ones) passed the JASO friction test to MA.
I'll throw the two quotes above together because my comment below will address both. If all these passenger car motor oils could supposedly pass JASO MA, and they've supposedly tested them to know that, then why don't they do the paperwork and pay JASO $400 to file the oil as officially meeting motorcycle JASO T 903 4-cycle oil requirements? Don't you think doing something so simple might enable the passenger car motor oil manufacturers to sell more oil to motorcyclists if their oil will also pass JASO T 903 specs? BLS - that list of JASO oils is world wide, and not a whole bunch of them are available in the USA. Does that RC45 manual actually call out 5W-30 SN? Viscosity "doesn't matter" ... ? Don't listen to Blackstone, they are not tribology experts, only oil testing experts ... the two are not always connected.
Originally Posted by BusyLittleShop
JASO has approved 1,537 oils as of Dec 2019 which covers virtually everything on the market... From 0w to mono grades... from 30 to 60 multi grades... from Auto to Cycle oils and yet not a single oil is JASO tested to have defeated a wet clutch... in fact the results of their market surveys are in a manner such that particular names of submitters and their oil products are not identifiable... so NO I don't see JASO as valuable as you do...