I thought it was already banned for the 2004 AMA series'? I have read some stuff on the web about various riders thinking about riding 4 strokes instead of 2 strokes as a result. I guess it's hard for them to tune the 2 strokes to get the kind of power out that they are used to now that they have to run unleaded. I think the whole unleaded issue is a result of FIM rules, not sure about that though.