Valcourt, QC 3, BRP’s 2014 Ski-Doo MX Zx 600RS features major changes: the snowmobile will turn quicker, stay straighter in the bumps and have stronger starts. These changes come with the move from the Rev-XP to the Rev-XS platform and refinements to many systems for pure race track performance in both snocross and cross country.
Primary on the Ski-Doo race only sled is a move to the Rev-XS platform that features improved ergonomics, improved aerodynamics, better rider protection and better air intake system for the engine. The racers will have more room in the cockpit and be able to move forward for easier cornering with the rounded side panels borrowed from the Summit line of snowmobiles—while getting better wind and snow protection from the sleek XS shape. The design incorporates large mesh covered vertical openings on both sides of the machine for unrestricted intake flow to the engine. Plus there is easier access to servicing of everything under the hood.
The chassis changes are significant also with a longer overall length, new rear suspension geometry, new steering system and refined front suspension. Most noticeable is the lengthened and tilted tunnel at the rear to better handle tail landings on the new 128-inch length track. The rMotion Racing suspension gets reworked with longer rails to match the track, a 2.75-inch (70 mm) longer front arm with new mounting points, revised coupling system and completely recalibrated KYB Pro 40 shocks. The suspension geometry changes and longer track will provide much better traction for starts and better bump absorption in the nasty snocross style bumps.
The front of the MX Zx 600RS gets a new top A-arm mount and new rack style steering system with increased leverage. The new mounting location of the A-arm provides better caster characteristics as the suspension cycles through its travel and the rack steering system eliminates any bump steer while taking less work to turn. Steering effort is reduced enough that racers will feel like power steering is a part of the changes. Additionally, the spindle length increases 5mm and the top ball-joint and spindle have increased tapered mating surfaces for a 135 percent strength increase.
Complimenting the platform and chassis changes are some engine updates to the cylinder and intake system. The cylinders will have tighter tolerances and better finishing for improved flow, while the carburetors increase to 40mm in size. Combined with the new intake tract, V-Force3 carbon fiber reeds, and less restrictive muffler, racers will see better performance from low in the rpms all the way to peak power output at 8400 rpm.
Making all the components work together optimally has kept the Valcourt Race shop busy since last fall. Many parts come directly from the factory Open Mod sleds and lessons learned from racing last season have been applied and advanced from as late as last April. Racers can expect new calibrations in the suspensions systems, clutching and engine; all geared to get the most from their machines.
Recap of changes:
• New Rev-XS Body Style
• New, Longer Rear Suspension
• New 128-inch Track
• New Longer and Tilted Tunnel
• New Front Suspension Geometry
• New Rack Steering System with reduced steering effort
• Increased Cooling Capacity
• Improved Clutch Calibration
• Improved ECM Calibration
• 40mm Carburetors
For more information on Ski-Doo snowmobiles visit www.ski-doo.com, or the On Track blog site for racing specific information.