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More than a decade has passed since Yamaha pioneered the 4-stroke mountain snowmobile segment with the introduction of the RX-1 in 2002. The RX-1 rocked the industry and came at a time when 2-strokes were rapidly declining in the motorcycle world. At that time the future of 4-stroke snowmobiles looked bright.
Yamaha continued their assault with several consecutive years of new 4-stroke models through the rest of the decade. Arctic Cat, Polaris and Ski-Doo also came to market with 4-stroke engines, but the other three manufacturers shied away from a 4-stroke mountain sled.
Yamaha’s barrage of new product finally slowed around 2008, but still remained the sole manufacturer of a 4-stroke mountain snowmobile until Arctic Cat launched the M1100 turbo in 2012. Now, after a seven year hiatus from having a new mountain sled, Yamaha is at it again with the all new SR Viper M-TX.
The SR Viper M-TX features the 1049cc triple cylinder 4-stroke from the now extinct Nytro in an Arctic Cat ProClimb chassis. This sled is the result of a supply agreement between Arctic Cat and Yamaha started in model year 2014. Ironically Yamaha’s only real competition in this segment comes from Arctic Cat’s M9000. Using essentially the same chassis as the Viper, the M9000 features a Suzuki built twin cylinder turbocharged 4-stroke. Yes, you can buy the M 7000 Sno Pro from Cat, which is basically the same thing as the Viper M-TX, however, Yamaha has an approved turbo available for their similar sled. So basically consumers have two choices for a big 4-stroke mountain sled… it might not be politically correct to say, but either a turbo Yamaha/Cat or turbo Suzuki/Cat.
Turbos
One sure way of turning up the fun factor of any machine is adding a turbo, and both the Yamaha and Arctic Cat 4-stroke mountain sleds are available with them. The Cat comes from the factory with an intercooled turbo and Yamaha has a dealer installed factory approved MPI non-intercooled turbo option. Yamaha further sweetened the deal for spring buy customers making it pretty affordable to add a turbo.
The added benefit of turbo performance as opposed to naturally aspirated performance is the turbo compensates for the loss of oxygen at higher altitudes. Where a naturally aspirated engine loses approximately 3 percent of its power for every 1,000 feet gained in elevation, the turbocharged engine still churns out the same power all the way to the top.
We have ridden both the Yamaha and Arctic Cat with and without turbos and the difference is huge. For high altitude riding the turbo helps bridge the performance gap to the lighter 2-stroke competitor machines and is essential if you plan on riding aggressively in the mountains.
Yamaha SR Viper
The Yamaha engine and Arctic Cat chassis combo shocked pretty much everyone when it was announced in 2014, but now in its second year we are getting used to it. It’s strange to see two competing companies working together and probably harder to accept is seeing the different parts together. It’s like trying to accept a new step-brother into the family. The refined engine sound mixed with a distinctly Cat feeling throttle is interesting, but setting aside sentimental brand loyalties, the result is a really good snowmobile.
Without doubt the SR Viper M-TX is the best mountain sled Yamaha has built in a very long time. The sled combines a solid engine with a proven chassis and the product is a sled that is powerful and handles well. If there was any doubt, Gavin Balls proved the capabilities of the Viper with his 700 improved win at the 2014 Jackson Hole World Championship Hill Climbs, marking Yamaha’s first ever 4-stroke class championship in the near 40-year running of the event.
Arctic Cat M9000
“Is that a 900?” It’s one of the most common questions you get from other riders when riding a M9000. The answer is no, it’s an 1100 turbo 4-stroke. It carries the name because of Cat’s numerical naming of its models based on horsepower in relation to each other and not the standard way of naming based on engine displacement. Rated at 177 hp the 9000’s CT-4 engine is the heavy hitter in Arctic Cat’s line and carries the proud title of highest horsepower stock engine in the industry.
Arctic Cat has had a tough mountain machine in the ProClimb chassis, and the 9000 shares many of the same components as its oil burning brothers in the M-Series line. The 9000 is available in a Limited 162 model that comes with a tunnel bag, goggle bag and limited graphics, or an HCR model with upgraded FOX Evol shocks, ice scratchers and race inspired graphics. Like the Yamaha, both models utilize the 162x2.6 Powerclaw track and mountain rear suspension.
The Yamaha SR Viper M-TX and Arctic Cat M9000 share many of the same chassis parts with the engine and clutches being the main differences. Other subtle differences like handlebar riser and slightly different bodywork exist, but in terms of suspension and handling, the sleds are very similar.
Catching on?
Due to its weight, the 4-stroke engine has been slower to catch on in the mountains than in other segments of snowmobiling, but it still has its niche in the market. For some riders the pros of a 4-stroke outweigh the cons, and then there’s the guys who buy them for no other reason than just to ride something different than everyone else.
For riders looking for the fastest sled out there,nothing beats a turbocharged 4-stroke. They have industry leading power from the factory and the potential for unlocking a lot more power with aftermarket upgrades. Then there are the benefits of an engine widely regarded as more reliable without burning oil. Both Arctic Cat and Yamaha have reliable product in this segment, and it speaks to the health of the industry to see new things happening again with 4-stroke mountain sleds.
Off the record, but we put it on!
The history of mountain 4-stroke snowmobiles shows us that in 13 years, there have not been DRASTIC changes. But it’s not for lack of trying. In the bike world Japanese manufacturers turned their back on 2-strokes years ago and with a huge share of the market were able to force the bike market towards 4-strokes. Yamaha tried to do the same in the snow but their efforts have been less successful than in the motorcycle world.
Questions remain. What are the reasons only two OEMs offer a 4-stroke mountain sled? Will we see Ski-Doo or Polaris play in this market with a new super-lightweight
4-stroke? Will we see more hillclimb wins? Time will tell! We know the blue team is hoping so and putting money into the RMSHA program.
What about naysayers that preach 4-stroke mountain sleds tire you out much faster? It’s true that weight is weight when you are stuck, but in our opinion, if we bought a 4-stroke for the real mountain riding we do, we wouldn’t buy one without a turbo, or supercharger. These do compensate in all but a few static situations.
There is almost no end to the crazy horsepower you can get out of a 4-stroke which is extremely tempting for a lot of big-climb riders. Check out “4-Stroke Hill” in Revelstoke, British Columbia sometime and you’ll know what we are talking about. Pointed straight up, there’s not much these things can’t climb!
That being said, many have asked us; is the novelty of climbing wild chutes at the risks of avalanches is scaring people into the trees? Is mountain riding basically going to technical boondocking, the likes of Chris Burandt and Dan Adams have made a living on?
We can’t tell the future, but mountain riding is evolving and while some dig the challenge of tree-filled sidehills, many mountain riders still want the thrill of the big power and big climbs, that’s where 4-stroke turbos still excel. The 4-strokes are slowly closing the weight and manueverability gap too!
We are waiting to see what happens, but mountain sled evolution continues and 4-stroke, and 2-stroke, evolution occurs hand-in-hand. It is only getting better in the mountains!