In one of the dirt bike forums, we have been trying to sort out the reformulations Yamalube has undergone. This is what I have learned....

Some interesting comments here: http://www.bikernewsonline.com...ands-yamalube-oil.htm


"I noticed around the motorcycle forums, engine oil is always a popular topic of discussion, with Amsoil salesmen constantly bashing Yamalube and other brands with charts and quotations. Whether these studies and comparisons are legit, I don't know. But I imagine Yamaha recognized there was some validity to it and chose to beef up its Yamalube line."

Yamalube has been reformulated (both different viscosities and different chemistries), and even the 08 owners manuals I have seen, don't seem to reflect these changes! For example, my XT225 (one sweet little commuter bike!) specs 20W40, but there is no longer any 20W40 in the lineup....

http://www.yamaha-motor.com/sport/yamalube.aspx


Your dealer should have a new applications chart, that supersedes any previous owner's or service manual information! See if you can get a look at it. I will try to post one if I can find it.

There is an old school petroleum oil, in traditional weights of 10W40 and 20W50. A synthetic/petroleum blend in 10W50 and 0W30 (snowmobile). And, a full synthetic in 15W30 and 15W50. All are JASO MA and wet clutch safe. None of the literature says that any of them are API SG. I personally always like to pick an SG oil, because that insures you that it at least has a minimalist anti-wear additive package!

The full synthetic is probably PAO based (my own hunch based on the price), and ester fortified. It is subclassified as JASO MA1, which means it contains some friction modifiers, and is slicker than the other two varieties (yet not as slick as a JASO MB). This should result in better shifting, and higher engine performance.

 

Some good general reading about oils: http://www.thumperfaq.com/oil.htm


http://www.sportrider.com/tech/146_0308_oil/index.html