I signed on with Amsoil, I live near the town where they make it.
What you need to rember whatever it is and it's been said, is: WET CLUTCH. The oil in the bikes soaks the clutch. From a performance perspective in Trials Bikes where clutching is everything, we have noticed a big difference. Whatever they put into the oil for wet clutches makes a difference.
The manulal lays out what you NEED: API, SH OR HIGHER (e.g. SJ, SK or SL) AND JASO MA
I like Amsoil, works for me. As long as you meet these standards you will not have trouble with warrenty, no matter what you use.
IMHO you can do better than $50 a gallon for good oil buying Amsoil (can't speak to Mobile1) at $7 a quart that is still way under $50 and cheap insurance to care for an investment.
