also FWIW, castrol grandprix is good oil for valved motors like your banshee. They doubled up on the detergency over some of there other products (like the super). I ran it last year in rotax sled motor and was impressed how clean it ran, enough I started clearing the shelf everytime I found it. $2.22 QT wallmarche.
________ i payed 2.34 /qt on clerence at target.
i feel ripped off now :/
the oil seems to run good though. about the same as the grandprix that i used before. grandprix and 2t seem to smoke a bit more than yamalube or mobil 2t, but for the price i dont care.