7. 1973 Yamaha SC500
The Yamaha SC500 is one of two worst dirtbikes candidates on our list. A four-speed brute, this 1973-’74 two-stroke single ran hot, detonated fiercely, stalled constantly and seized regularly. After testing the bike, I noted: “It’s gray and black; so is a turkey.” Brutally fast, the SC-500 was cursed with state-of-the-dark forks and a pair of chromed shocks that would have faded on a busy barroom door. It shook its steering head like a dog coming out of a swimming pool and the rear end hopped around like the frame had a hinge in the middle. All things considered, the only thing this bike did right was not leak around the gas cap.