dirt bike 10w-40

A reader asks: Why does AMSOIL Dirt Bike 10W-40 have the JASO MA rating and not the JASO MA2 rating like the AMSOIL Metric Motorcycle 10W-40? How important is this? Our answer: Before we get into the finer details of JASO MA versus JASO MA2, let’s talk about the real-world difference between AMSOIL Dirt Bike 10W-40 (JASO…