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Polaris shows 2003 440 ProX racer

By Wade West
Published: October 15, 2002
 The demands for snocross racing are getting tougher each season. Year after year, the factories refine and reengineer their race sleds to become more track-specific and less trail rideable. Polaris upped the ante on its 440 ProX racer, making it even more snocross oriented. New driver ergonomics, more durability, lighter weight and a handful of new techno gadgets combine to define the next generation of Polaris racing.
Holeshots are the name of the game in tight track snocross racing. The first sled into corner one stands a good chance of prevailing at the checkers. Polaris engineers found that their sleds were losing that sprint in to the corner and it cost them position. One reason, they found, was that the pipe was losing upwards of 200 degrees from warmup to the green flag. The cold pipe robbed horsepower off the line, resulting in less-than-optimum holeshots. To fix the problem, Polaris turned to electronics. A new engine rev limiter button graces the left handlebar. Like Prostock drag sleds and bikes, the driver comes to the line, holds the button in, mashes the throttle to the bar and the engine sings at about 5000 rpm, just under clutch engagement. When the flag drops, let the button go and the sled roars off the line. The rev limiter keeps the pipe at operating temperature without bumping the clutch, and also gives the driver a quicker reaction time, as the sled is always ready to engage. The system is awaiting patents, so Polaris officials were fairly tight lipped about the specifics on how it works.
Polaris also turned directly to Moto Tassinari for its legendary V-force reeds. They are now standard equipment on the race sleds.

Clutching remains a focus, with improved calibration and performance from a new die cast Team Industries Rapid Reaction roller secondary and Polaris primary. Not only did developers shoot for the hard launch, but they also improved the sled's backshifting characteristics. With the tight track conditions in snocross, drivers get in and out of the gas frequently. Boggy shifting loses position.
Cornering was another focus on the new sled. Polaris revamped its front end geometry to further tighten the sled's cornering radius. A shorter, more aggressive steering arm is the main contributor. Additionally, the chromoly trailing arm and aluminum radius rods have been strengthened.

Walker Evans Racing shocks return to all four corners this season. The new units have compression adjustment clickers on the remote reservoirs. The new design is easier to tune and even more rugged than last season.
Spinning around a narrower skid is a new track. Measuring 14x121x1.675 inches, the new narrow Sno-X track was specifically designed for the greasy, mealy snow of a snocross track. Its deep lugs are built up of 80-durometer rubber, to be extra stiff. Their cupped design scoops the snow, instead of blowing through it.

Polaris' unique adjustable front torque arm has been modified for better durability. The system allows drivers to make a quick change in handling for tight tracks or venues with wider, sweeping turns.

Ergonomically, Polaris shifted riders three inches higher and two inches forward, thanks to a new mini racing seat. It's the first thing you'll notice about the ProX this year. The seat looks very similar to Ski-Doo's Rev seat, with its short length and taller height. Our seat of the pants impression is that Polaris has finally put the driver up high enough to easily transition from sitting to standing, without a lot of extra effort.

With the shortening of the seat, a black plastic piece shields the coolant crossover plumbing from danger.

Polaris moved the handlebars another two inches forward from the 2002 ProX, which also saw a move forward. Over the past two seasons, the bars have migrated a total of 5.25 inches toward the nose.

The engine itself has been kept mostly the same. The 440 Liberty has a new ceramic-coated pipe and recalibrated 34mm TMX hot dog slide carbs. Surrounding the engine, the bulkhead and mounting system have been reengineered to be beefier without adding weight.

The Mod Sled

Many local dealership employees and racers thought Polaris would pull the cover off its rumored mod sled at the Milwaukee snow show. While there was no official word of Polaris' factory mod program, there were plenty of mumbles. We expect Polaris to offer a very limited number of rolling chassis mod sleds for its top racers. Plan to see a tricked-out A-arm sled in red this season. Ski-Doo showed us all last year that a full factory mod program can yield solid success on the track, with the added benefit of building consumer acceptance for a radically new trail sled platform. We expect this will be what we see from team red this season.
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