It is almost shocking to see the improvements being made to Yamaha’s SR Viper M-TX sleds, now in only their second year....

     It is almost shocking to see the improvements being made to Yamaha’s SR Viper M-TX sleds, now in only their second year. Not that the 2015s worked poorly, quite the contrary, as many of Yamaha’s western dealers got caught short handed and ran out of inventory. This year the 2016s ramp it up aggressively and really make the 4-stroke mountain sleds demand even more respect.

      When we get to real-world differences on the snow, it is perhaps the new front suspension for 2016 that provides the largest improvements. The M-TX models feature a new 36” wide SRV-M front suspension. This sleek front end is ultra compact to reduce unwanted spindle and suspension component drag in deep snow with a narrowed stance for extreme maneuverability. It allows more aggressive lean angles for incredible side-hilling and powder turn capabilities. The new forged aluminum spindle joins new upper and lower control arms for reduced weight (2.4 pounds) while an increased caster angle improves side-hilling and ease of steering. A narrowed overall stance, elimination of the sway bar and shorter shocks greatly enhances deep snow agility.


     This new front end is shared with their Arctic Cat M-Series cousins, but from our experience we believe it has an even more dramatic effect on the Yamaha versions. With the new spindle, a-arms and narrow 36” width, this sled is much easier to throw on its side when aggressively maneuvering in tight terrain. The new spindle is laid back and does not dig into the snow. Along with a new caster angle and ski profile for 2016, we were surprised by the amount that rider effort was reduced and welcome this change as it makes the sled more responsive and agile. The trade-off (of course) is the M-TX is not as stable as it was motoring down a trail, but that is acceptable to most every deep snow rider.

      The 3” Power Claw track option is actually 2.5 pounds lighter than the standard-issue 2.6” lug height Power Claw and it works extremely well on the SR Viper M-TX platform. It provides a substantial improvement in traction and lift, which is a great fit for this sled’s 4-stroke engine. After riding both the 2.6” and the 3” tracks, we couldn’t really find a place where the 3” didn’t outperform the 2.6”. Problem is, the 3” lug height was only offered during the Spring Power Surge program. Our test riders believe this could be the best deep snow track option from anyone for 2016 and are most anxious to get one out on the snow for long term testing.


      We really like these sleds equipped with the Mountain Performance Turbo kit offered through Yamaha. Scratch that, we love it, and for many Viper M-TX riders this will be the only way to go. Mountain sled performance is all about flotation and power to weight ratio, and with the turbo kit installed the M-TX horsepower is pushed to a level high enough to overcome the negative weight penalty of the 4-stroke engine. This combination allows us to carve through some of the nastiest terrain found in the West and can provide the horsepower to get you out of trouble (or into even more). Definitely, we would prefer the 162” x 3” Power Claw track when riding an SR Viper M-TX with a turbo as the extra horsepower can require added traction in most conditions.

      For the few who chose not to add the giggle maker (turbo) we would stick with the 153” length unless the average riding conditions are waist deep or better at which time we would bump to the 162” x 3” setup. The 153” x 3” track feels more agile than the 162” and takes less rider input to make the sled react. We see this sled being perfect for the rider who wants the rock-solid reliability of the Yamaha 4-stroke engine and wants to mountain ride, but may not have the desire to slay the nastiest backcountry.


      Base models come with coil-over shocks up front and in the rear, where the SE models features Fox FLOAT 3 shocks with air springs up front and on the rear arm, along with more vibrant colors and a lightweight brake disc. Spring-only LE limited models ramp it up with taller 3.0” lug height Power Claw tracks and replace all of the shocks with Fox FLOAT EVOL units for the ultimate in adjustability. The LE also adds even more goodies, things like a heated seat and a rear storage bag as standard issue. They’re all good, with the shock packages and track lug heights being the main differences between the three trim levels. All models get the new front end, new skis and a super-short windscreen for 2016. The (standard) M-TX 162 is actually a new model for 2016, as last year the 162” was only offered in LE or SE versions.

      We can easily state with confidence that the 2016 Yamaha SR Viper M-TX models are the best 4-stroke mountain sleds ever offered, especially when you fit one with a turbo (the Spring program pricing on this is incredibly good). Yes, they weigh more than a lower-powered 2-stroke, but the power-to-weight ratio is overcome with the boost giving you more power at all elevations. But, at the end of the day, it is the consistency and reliability of this engine package that seals the deal. Two-stroke motors can only dream of making this kind of power with this kind of reliability. 4-stroke mountain sleds keep improving, lasting far longer with far more power. Now they handle even better as well. You will continue to see more of them out in the powder and in the hills, and with good reason.

      The 2016 Yamaha SR Viper M-TX 162” sells for $12,699; the 162 SE is $13,399. The M-TX 153” goes for $12,299 and the 153” SE is $13,199.

From the September 2015 issue of SnowTech Magazine.

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