Ski-Doo Unveils Powerful New Four-Stroke Engine

Two weeks after pulling the wraps off of the lowest-emission two-stroke engine in the snowmobile industry, Ski-Doo took solid aim at the four-stroke market with a new, Rotax 4-TEC 1200 engine it showed in Ontario January 31.
The engine makes 130 horsepower at 7000 rpm, according to Ski-Doo officials, meaning it will compete directly against Yamaha Nytro models but will do so with a lower-revving package.
The Rotax triple will be found a 2009 MX Z 1200 and GTX-SE models that feature modified versions of the REV-XP chassis which debutted in model year 2008. The chassis that fits the four-stroke is called a REV-XR
Ski-Doo also announced details on its 2009 Expedition that features yet another modification of the REV-XP chassis, called the REV-XU.

The New Four Stroke Engine
Ski-Doo’s new four-stroke boldly takes the brand into direct competition with Yamaha’s four-strokes. Previously, Ski-Doo positioned itself as the clean two-stroke company while Yamaha staked claim to majority of the four-stroke market.
While Ski-Doo has had a couple of four-stroke models in the past, they were moto-vated by less-powered Rotax engines designed for other purposes. Ski-Doo engineers assured us this new four-stroke was designed from the ground-up exclusively for snowmobiling.
The fuel-injected inline triple actually displaces 1170cc and features dual overhead cams, four valves per cyclinder and a counterbalancer. It engages at 2800 rpm but pulls best once the RPMs get about 5000.
Ski-Doo officials claim the engine makes about 100 foot-pounds of torque, 10 more than Yamaha’s Genesis 130FI engine found in the FX Nytro models, while having notably lower emissions. Those same officials say the engine should easily get 18.3 mpg. High tech features include valve “finger followers,” a feature pulled from Formula I race car engines that reduces mass in the valvetrain and also makes the engine easier to service. Rare earth magnets are used in the magneto.

The New Chassis Platforms
When Ski-Doo unveiled its REV XP platform last year, it was only the start of what Ski-Doo officials are now calling the REV X platform. Here’s how it play out: The “XP” platform is for high performance, two-stroke models; the “XR” is a very similar, lightweight chassis for four-stroke and some touring-based models; the “XU” is for utility models.
When compared to the original XP, the XR chassis features slightly wider bodywork up front and different motor mounts to accomodate the new, larger engines. It will also be the base for premium GTX models.
The XU, meanwhile, will feature a wider tunnel and wider running boards and what Ski-Doo is calling a “rugged, SUV-style belly.”

The New Sleds
The snowmobiles Ski-Doo unveiled this week are the MX Z X 1200 4-TEC, the GTX Special Edition and the Expedition TUV.
The MX Z 1200 is the first MX Z with a four-stroke engine. It features a traditional MX Z featuring position and feel. It weighs in at 499 pounds, making it notably heavier than the two-stroke Ski-Doos but notably lighter than other four-strokes on the market, and several two-stroke models as well.
The GTX Special Edition also features the 1200-class four-stroke, but it gets a plethora of touring features as well. They include adjustable steering, a new ACS air shock rear suspension, terrific wind protection, luggage as standard equipment and new “SilenTrack technology.
It’s got a comfy two-up seat, 12-volt outlets front and rear and a classy look. The ACS air shock rear suspension can be adjusted on-the-fly from the drivers seat to five different positions. It is in the XR chassis platform.
The Expedition TUV, meanwhile, is in the XU platform and features a great look and many utility features. They include a synchomech transmission with reverse, an extra-high windshield and a 20- by 156- by 1.25-inch track.
For more details, visit, or see the Spring issue of Snow Goer when it mails in early March.

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