2005 Hepler raced a limited AMA 125cc West Region Supercross series, winning the Phoenix round and earning a podium finish at Houston... Raced in the AMA 125cc Motocross Championship, earning overall wins at New Berlin, N.Y., and Delmont, Pa., with three additional overall podium finishes... Raced with American Suzuki team.

2004 Hepler earned second-place finishes in the AMA 125cc East Region Supercross races at Houston and Atlanta, and was runner-up for the series title... In the AMA 125cc Motocross Championship, Hepler earned six overall podium finishes, and was runner-up for the title again... Named AMA Supercross/Motocross Rookie of the Year... Raced with American Suzuki team.

2003 Hepler entered the last three rounds of the AMA 125cc Motocross Championship, earning solid top-15 finishes.