The 15-50 car oil until recently carried the sj sl ok for motorcycle use api label. You can still find some old stock from time to time. Whether they actually changed the formula with the new stock is anybodys guess. I have used it for a couple of years with no clutch slipping. I bought my local wal-mart out of the old stock a while back. It was going for Ten dollars for a five quart jug.
