Duncan Racing was founded in 1977 in Santee, California by Danny R. Duncan. The company was originally founded under the name of Danny's Machine Works. For the initial 8 years Danny's Machine Works became very well known in the southwest United States as one of the premier hi-performance motorcycle and ATV speed shops. The company specialized in 4-strokes doing many hi-performance articles for the likes of 3-Wheeling Magazine. Besides building a very strong reputation for high quality work Danny's also did work for many top So. Cal. Motocross racers, including Ricky Johnson.

In mid 1986 the company changed it's name. Loren Duncan, Danny's oldest son, took over the reins and changed the name to Duncan Racing International. In late 1986 Loren hooked up with former Team Honda Factory rider Marty Hart doing all of his mechanical work for the balance of his ATV racing career. Through Marty, Loren met and became business partners with Paul Turner the founder of Paul Turner Racing Engines and engine builder for Team Honda. In 1989 Paul had made a colossal R&D break through in the mountain bike industry designing the first pair of Rock Shox (suspended bicycle front suspension). The idea quickly took off and Paul left the ATV industry to pursue his mountain bike interests. Duncan Racing absorbed all business operations for Paul Turner Racing Engines and the Paul Turner line of pipes, silencers and porting. Since 1989 Duncan Racing has owned all PTR products and has designed and manufactured all ATV related items.

The decade of the 90's let Duncan Racing establish itself as the premier hi-performance ATV Company in the industry. Winning more Pro ATV races worldwide than any other company by a 5 to 1 margin. While other companies talked fast, Duncan Racing kept their head down and concentrated on building the best and most reliable products on the market, while still maintaining a very service oriented customer relationship. With an active customer base of almost 15,000 people, over half of Duncan Racing's customers are recreational enthusiasts that enjoy riding their ATVs. Duncan caters to all racers from the National Champion Travis Spader to the local track beginner. The thing they all have in common is the desire to receive the highest quality, most reliable products from the most knowledgeable sales staff. 

Many of the top ATV riders in the world have ridden Duncan Racing bikes or used Duncan products to win their countless races and championships. Without the excellent testing and R&D from these riders it would be difficult to achieve the high level of performance Duncan Racing has set for itself. We would like to thank the following riders for their contributions; Marty Hart, Doug Eichner, Bob Sloan, Travis Spader, Randy Howard, Matt Smiley, Chad Duvall, Ben Jackson, Don Turk, Rodney Gentry, Barry McCarty, Doug & Mike Roll, Charlie Shepherd, Brian Fuller, Tavis Cain, Chad Lohr, Mark Ehrhardt, Garry Denton, Steve Stroud, Paul Winrow, Richard Cole, Paul Anderson, Marc Gobert, John Mitchell, Joel Bontoux, Stuart Walker and Pascal Bocheau. The new millennium started with a bang for Duncan Racing with factory team rider Travis Spader winning the AMA 250 Pro ATV National Championship and Doug Eichner/Paul Winrow winning the 12 hrs. of Pont De Vaux World Championship Endurance race. Duncan also brought out their new 32-page catalog. Plus the debut of the new PC 2000 Power Valve Cylinder.