Good question. Most manufactures try to keep that a secret. I personaly run Brad Penn "green oil". I buy it by the case on Ebay. http://www.bradpennracing.com/
I've talked to a lot of the guys at the local tracks. Both drag and cirle track and they swear by the stuff. I noticed it quieted down the engine noise in my bike quite a bit. The bike also seems to be running cooler.
