Heading in a Radically New Direction Feast your eyes upon the all-new 2014 Yamaha SR Viper. Powered by the Yamaha 1049cc “Nytro” engine fitted...

Heading in a Radically New Direction

Feast your eyes upon the all-new 2014 Yamaha SR Viper. Powered by the Yamaha 1049cc “Nytro” engine fitted with Yamaha primary and secondary clutches, this new sled has so much new and different going on that it might take a few moments for it all to sink in. The Nytro engine, the three-cylinder rip-snorting arm-stretching 4-stroke that is arguably the single best engine in the business, has been dropped into a new chassis that will give you the ride quality and handling capability that we have all been lusting for with this world-class engine package. Careful what you wish for, because it is right here, right now.



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This new (for Yamaha) platform is being called the SRV Chassis, featuring a two-piece, tipped-tunnel that puts the rider into the ‘attack’ position. It is tapered 15 inches at the top (seat base) to the wide floor boards. This facilitates a narrow seat for ease of movement without sacrificing track width, clearance and stability. The Pyramidal upper frame design adds strength without weight. The upper frame consists of several geometrically triangulated spars, and forged steel housing brackets ties the frame spars together. The front shocks mount directly to the leading spar at angles designed to transfer the trail force into the strongest part of the chassis.



Up front we find 30-degree A-arm mounts. Force is transferred into the chassis at a 30 degree angle from the centerline. The swept-back attachment points affect the sled’s approach angle, preventing it from diving directly into holes or ruts. Optimized mount points spread the load more evenly into the frame reducing flex. Tall, lightweight forged spindles create a wide a-arm layout, all for added strength. The tall length allows for the wide A-arm spacing to reduce stress and chassis flex. The steel bulkhead sub-frame provides rigid mounting points for the shocks and A-arms and reduces flexing for more accurate shock calibrations.



Another departure from what we are familiar with on Yamaha four-strokes is how the rear-exiting exhaust is gone. Instead we now find a forward, or centralized muffler location, up in front of the chaincase on the right side, just like most sleds have. The engine is tilted back in the chassis so the exhaust ports are located just above the jackshaft, with the stainless steel header pipe and main pipe still cooled by snow. This mounting location will reduce the weight of ice build-up and better centralizes the mass. This new arrangement actually helps to center almost 60% of the sled’s mass, a huge factor in how this new sled handles and feels as you ride it. We also find large running board cut-outs that clear out snow to allow easy foot movement on the running boards, another welcome feature.


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Yet another great improvement is the extended fuel range with the 40 liter (10.6 gallon fuel tank). Limited fuel range was such an issue with the FX Nytro models and its small fuel tank, but that problem has now been solved as well. There’s also a quick-disconnect seat that can removed in a matter of seconds, giving us fast access to the rear-mounted battery. The battery tray is molded right into the gas tank to reduce vibration and reduce overall weight. This new seat design is heated for rider comfort, and has a tall, thick saddle for excellent ride comfort and versatile ergonomics.



In the rear we find a Comfort-tuned with a 15 x 129 x 1.25” Rip Saw II track (2.86 pitch) wrapped around it. This track is excellent for trail riders as it helps to keep the skis on the ground during cornering, allowing a slight amount of side slip instead of biting and causing quick inside ski lift. Overall this track delivers a balance of traction on both hard packed and loose snow conditions and delivers excellent durability and top speed capability.



The Dual Shock SR 129 rear suspension rear suspension is a torsion spring design with a set of comfort-tuned HPG shocks (we believe they are Fox or ACT shocks, but Yamaha is simply calling them aluminum HPG shocks). This is a coupled rear suspension but with a “floating” front-arm pivot that doesn’t force the front arm to collapse immediately when the rear arm couples to it. This helps to control (or eliminate) ski lift during acceleration and maintains full front arm travel for reducing bottoming.



Up front we also find a set of comfort-tuned HPG front shocks with coil springs. Again, we believe these are ACT or Fox shocks but Yamaha is using the HPG designation in their descriptions. They have lightweight aluminum bodies and are rebuildable with internal floating pistons and tunable pyramid valve-stacks that resist fading and provide consistent performance.



Another major difference between the SR Viper and the FX Nytro is the rider protection. Instead of a narrow, sculpted body that provides little wind deflection we now get a wide body with excellent rider protection, along with a truly functional and stylish mid-height windshield.
Another standard feature aimed at pleasing the trail riders this sled is designed for is the large behind-the-seat cargo bag. Where the FX Nytro had zero storage capacity, this new cargo bag is a convenient way to carry extra gloves, goggles and trail snacks and is both secure while riding and easily removable at the end of the day.



By now you might have realized this new sled has a lot of features that look familiar, and you would be correct. Yamaha and Arctic Cat have a “mutual supply agreement” where Yamaha supplies the engines and Arctic Cat supplies the chassis and assembly. This is an Arctic Cat ProCross chassis design, as the SR Viper is being built at the Arctic Cat factory in Thief River Falls, Minnesota for Yamaha, and to Yamaha specifications and quality control standards. This is no easy feat. What started out as an Arctic Cat chassis has been scrutinized and reviewed and changes have been made, make no mistake.



It is not accurate for us to tell you this is just an Arctic Cat with a Yamaha engine and clutches, as there is far more going on here. This is where it started, but has progressed far past that point. On the first pass, Yamaha came back with no less than 72 items they wanted changed to make this sled a Yamaha. Things like fit and finish items of the side panels were changed. The seats were not up to Yamaha’s liking, so we now have seats that fit better and are easier removable with latch on the back and a stronger seat base. In the chaincase we find a Borg Warner 13-wide chain with machined gears, not stamped gears and a smaller chain. We also find a manual chain tensioner, not an auto-adjust chain tensioner, so you will want to be adjusting the chain tension after the first 500 miles. This set-up is more to Yamaha’s liking and standards.



Yes, Arctic Cat now offers sleds in their line-up that also feature the same Yamaha engine, but there are now many differences between them. The calibrations started out very similar, but the SR Viper has Yamaha clutches so the clutching and responsiveness will be different. The skis are different, the side panels are different, the windshields are different, the snow flaps are different, so there are differences from ski tip to snow flap.



What about the engine? This is a Yamaha FX Nytro engine, but past that it is different. In this chassis it has a new intake and exhaust, so that means a new ECU and new programming. We’re told it now makes a couple more HP, and is perfectly happy with 87-octane fuel. It for sure sounds different than the FX Nytro, but it still pulls like crazy. Power and performance is not an issue in this conversion. This engine is still like a hammer, it just doesn’t break.



For the Yamaha trail riders looking for the engine of the FX Nytro but with world-class ride and handling, look no further. The SR Viper is going to be the comfort-tuned option with the 129” track length and will be a trail-rider’s delight. It is available at Yamaha dealers for $12,149.

From the September 2014 issue of SnowTech Magazine. To see all the great articles from SnowTech you have to be a subscriber to the magazine. Subscribe here – and have SnowTech delivered to your door.

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