1972 Yamaha SC-500

What Kawasaki did on the street with the H-2, Yamaha did in the dirt with the SC-500. This was easily the most powerful dirt bike of it's day, I believe. A friend owned one of the things, and I can attest to the fact that it was outrageously powerful. Top gear wheelies were a mere twist of the wrist away. It was the closest thing to a factory motocrosser that the average Joe could obtain, certainly.

Unfortunately, unless you followed a regimen of maintenance which was far more intense than the average privateer could manage, reliability of the SC was extremely spotty. We're talking a top-end job after every race, and worse, a bottom-end rebuild every 6 races or so. Still, with this bike, Yamaha served notice that they were playing for keeps!