Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/783081
P114 CN III EMPIRE OF DIRT BY STEVE COX T he AMA Production Rule (first instituted for the 1986 season) states that any motorcycles raced in AMA Pro Racing motocross or supercross events must be homologated, meaning that a certain number of the machines must be avail- able for purchase inside the U.S. prior to anybody competing aboard these motorcycles in said AMA Pro Racing events. And a number of things must remain unchanged from a production motorcycle even on a full-factory race machine like you see under Ryan Dungey or Eli Tomac. But in order to conserve space, I'm not going to go on and on about all of the production rules. In this column, I'm speaking purely about the chassis. This is how the chassis is addressed in the AMA rulebook: Frames must remain stock, as can be purchased at a dealer, along with the rear swingarm. (Exceptions are made for adding strength to these chassis mem- bers.) The engine-mount locations, along with the steering-head, swing-arm pivot point, and rear suspension linkage point must be the same as the homologated model. Subframes can be replaced, but must be made of steel, alumi- num or titanium (not carbon-fiber, unless the stock machine comes with a carbon-fiber subframe), but the subframe must be of a similar design and use the same mount- ing points as stock. Back when this rule was made, it seemed to make sense, as the machines run by the manufac- turers—especially Honda—were so different from stock that it seemed as if nobody could compete if they weren't on the factory team. However, the case I'm about to make in this column is that I believe the production rule—at least in terms of the chas- sis—may have outlived its useful- ness for a number of reasons (at least in the 450cc class). Here's my reasoning: This sport has taken some amazing leaps, especially over the past 15 years or so. Mod- ern 450cc four-strokes are so incredibly powerful that even the best racers on the planet tend to detune them. Even Ryan Dungey, Chad Reed, Ken Roczen, Eli Tomac, etc., choose to have less outright power than they could have, and instead choose to try and customize how their motor- cycles deliver the power. While the motorcycles have gotten so much better, the tracks have struggled to keep up. The distances between jumps have increased since the two-stroke days simply because 450cc four- strokes can jump so much far- ther, and it was actually danger- ous to leave the gaps the same because the racers are going so much faster through the jump transitions. Feld Motorsports and Dirt Wurx have cut down a lot of the traditional supercross bowl FULL-FACTORY PHOTOGRAPHY BY STEVE COX David Bailey's works Honda RC 500 of the early '80s is one of the most iconic MX race bikes ever.