WHAT IS IT? The Loudmouth is a CNC-machined airbox ring that replaces the stock airbox ring and air filter mount.
WHAT’S IT COST? $150.00 (Honda, Suzuki and Kawasaki), $190 (Yamaha)—            (631) 445-6865       or www.loudmouthmx.com.

 For a simple air box ring, the Loudmouth air filter system has its feet in a lot of fires. It makes the air filter easier to access. It eliminates the bulky and restrictive filter cage and mounting bracket. It does away with the backfire screen (and replaces it with a fireproof foam No-Toil air filter). And it claims to increase horsepower, torque and throttle response.

   The Loudmouth kit consists of a CNC-machined aluminum adapter plate that replaces the stock plastic airbox intake plate. It many ways it is similar to the aluminum plates that have been sold to eliminate leakage around the front of the air boot. The difference is that the Loudmouth goes inside the airbox housing, where it serves as a new mounting point for a No-Toil Super-Flo clamp-on filter. The filter is held in place with a large hose clamp that goes around the extended lip on the aluminum ring. To remove the No-Toil filter all you have to do is loosen the hose clamp and pull the filter out. With the LoudMouth, you eliminate both the blockading filter cage and restrictive backfire screen.

 Here’s a list of things that stand out with the Loudmouth quick change air filter system.

   (1) Performance. Although designed for ease of use, the Loudmouth’s airy design does have performance
benefits. The wide open intake opening allows for a larger volume of air to flow into the engine, and with no cage, wire screen or cage mounting bracket, the air is unrestricted into the carb throat. On the dyno the Loudmouth actually showed a horsepower increase, across most rpm settings. On the track, test riders felt the power increase as more transitional power across the midrange. We didn’t have to re-jet.

   (2) Installation. MXA tested the Loudmouth on a 2009 Yamaha YZ450F, and thanks to the simplicity of Yamaha’s airbox design, it could be installed in less than ten minutes. It takes longer on a Kawasaki, Honda or Suzuki because their airbox rings bolt on. It is necessary to seal the plate with Hondabond or Yamabond.

   (3) Air filter. Every Loudmouth system uses the same air filter whether on a CRF, RM-Z, KX-F or YZ-F. It uses a rubber lip-style filter (called a green weenie decades ago). It is easy to change and the extended lip of the Loudmouth ring makes it impossible for dirt to fall into the carb. Best of all, you don’t have to fish around with the wing nut bolt to get the filter installed. 

WHAT’S THE SQUAWK? No complaints. We’d run the Loudmouth just because it makes cleaning the filter easier. The improved powerband is a bonus.