Vuillemin made his first AMA motocross race appearance when he competed in three rounds of the 1996 AMA 125cc Western Supercross championship. In the 1996 125cc motocross world championship, his results improved with a 16th place finish. Vuillemin returned to compete in the 1997 AMA 125cc Western Supercross championship competing as a privateer with assistance from the FMF racing team. He posted first and second place finishes in six races and, was ranked fourth in the championship final overall standings. Riding for the Yamaha of France racing team in the 1997 125cc world championships, he ended the year ranked 6th in the final overall standings.