Go look in the tracker inspiration thread at the CB750/Champion frame flat tracker that Rick Hocking and a few others rode. Take inspiration and knowledge that there did exsist multi-cylinder dirt trackers before the AMA's stroke of "genius" in banning them in late 1975. After the first win on a national level by a bike first entered that day, first seen by the rider that day, first ridden by that rider that day, and Kenny WON on it that first day! By the way, it seems KR's opinion on the bike has softened with the years, read his comments in the most recent issue of Cycle World.
I was at Indy that Saturday night in 1975 and saw it first hand, along with the other 4 TZs and three or four Kawasaki H2 750s. No one crashed their brains out, they all walked away that night, but that wasn't good enough. They threatened to change Grand National racing. If you really want to know more, find the January 1976 issue of Cycle World and read about the work that went into the bike, the reasoning, the testing, and you know the final results... a win and a ban. It wasn't the major threat, but it was an avenue for a privateer to use his roadrace engine (AMA paid points for short track, half mile, mile, TT, and roadracing back then for #1) to make a competitive mile bike for the cost of a rolling chassis.