October 20, 2009

Mountain 4-Strokes



2010 is a key year in their evolution

Yamaha Apex MTXTwenty-ten was shaping up to be a significant model year for four-stroke mountain sleds. It still is, but what did (or didn’t) happen was enough to make us at SnoWest separate the four-stroke mountain sleds out from the two-strokes, bunch them together and compare them head-to-head. But here we are in the October issue and all we really have to cover are the Yamaha FX Nytro MTX and Apex MTX.

Early spring reports had Ski-Doo on tap to release a Summit version of its 1200cc four-stroke. The sled had piqued our interests, given the success that Yamaha has cultivated in its four-stroke development. We were extremely curious to see what Ski-Doo could do with a thumper and its lightweight X-platform. The second factor in our creating a four-stroke-only segment was the fact that Polaris chose to drop the 700 RMK from its lineup back in February. In the past, we have put the Nytro MTX in the “700” class alongside the 700 RMK. No 7 RMK meant that the Nytro was now an orphan sled. So as we went about riding, photographing and testing the 2010 models, we did so with the intent of a Ski-Doo-and-Yamaha four-stroke feature and scrapping our 700 class story.

But just before we showed up in Grand Lake, CO, for the 2010 snow shoot, Ski-Doo announced that it would be postponing the Summit 1200. Word is that they had units ready to go for pre-production, but the decision makers weren’t satisfied with the sled’s power-to-weight ratio, a standard set high by the Summit XP. So now we have to wait and see if they go for it again in 2011.

Then, in June, Polaris announced that it was bringing the 700 RMK back. The news was welcome in our offices, but now we had the 700 class back, but without any head-to-head testing and photography (the 700 RMK may be virtually unchanged from ’09, but the 2010 Nytro MTX SE is significantly different from the previous year).

So we’re sticking with Plan A. This is your four-strokes-only mountain sled report.

2010 Yamaha Apex MTX

Lightweight rear suspensionFrom reading the 2010 New Features story in the September issue of SnoWest, you already know that not much changed for the Apex MTX. It is still the biggest, baddest 4-stroke mountain sled available and is hugely popular among the turbo crowd.

In 2006, the Yamaha Apex set a new standard for mountain 4-stroke performance and handling. Though those characteristics have been surpassed by the 2010 Nytro MTX SE, the Apex still holds a special place among western riders looking for a platform to build the biggest chute-climbers you’ve ever seen.

Shipping And Handling

Lightweight rear suspensionThe Apex MTX weighs in at 600 pounds and change. That is a lot of bulk, but it handles it better than you would expect. The 16x162x2.25-inch Maverick track gives the Apex enough surface area on the snow to support the sled without becoming a trencher for the water company. Thanks to the powder skis and the Maverick track, the Apex floats through powder (its most enabling snow condition) with agility. We like its seat and rider-forward positioning. Its handlebars are tall with the proper width and hook ends for mountain riding. The mountain strap is well-placed. The Apex benefits from a double-wishbone front suspension and the ProMountain 162 rear suspension. The fact that Yamaha is keeping the real goodies on the Nytro MTX rather than spreading them over to the Apex hints that a revised 150 hp 4-stroke sled is possibly just around the corner. It would have been easy to put the Fox Floats on the front of the Apex and a ProMountain Air 162 rear suspension under the Apex. But if Yamaha engineers were going to do that, why stop there? Why not cut and taper the running boards and shave 25 lbs. off the chassis? We think that if Yamaha were going to just do another SE version of the Apex, we would have seen it this year.

But that’s not to say the Apex isn’t a serious consideration as a mountain sled right now. The throttle response is super-crisp and the Genesis 150FI engine puts out 150 hp with broad, trademark 4-stroke torque. While most mountain 4-stroke riders will lean towards the new Nytro MTX SE this year, the Apex MTX will still fill the needs of many Yamaha faithful looking for that one extra cylinder and 20 more horsepower. Especially if there’s a turbo involved.

2010 Yamaha FX Nytro MTX SE

NytroThere are two versions of the 2010 FX Nytro MTX: the standard MTX with a 153 track; and the MTX SE, available in both 153 and 162.

First, let’s go over the changes to the SE compared to the ‘09 Nytro MTX. Yamaha’s goal was to decrease the Nytro’s weight and improve its deep snow mobility and performance—an area that is already a challenge to the natural characteristics of a 4-stroke.

Yamaha changed the front suspension, lightening the components and altering the geometry to work better in the mountains and removing the sway bar. Working closely with Fox Racing Shox, Yamaha helped develop the Fox Float 2 air shock—a springless successor to the original Fox Float.

Yamaha engineers built a new rear suspension that is basic and simple—endearing words to mountain riders. The new skid features a shallower 18-degree approach angle and a 2.8-degree rear tip up for easy turning, lightweight rails and runs a 15x153x2.25-inch or 15x162x2.25-inch single-ply Maverick track. Fox Float 2 shocks were used for the new ProMountain Air rear suspension as well. The 2010 ProMountain Air rear skid is 10 lbs. lighter than the ‘09 ProMountain suspension.

To improve the way the Nytro MTX handles deep snow and sidehilling, engineers turned to the tunnel. Narrow, shorter running boards replace the old, wide, full-length boards that had a tendency to hang up in deep snow. The tunnel has a new 11-degree angle with a narrow, slim tail section and lightweight rear bumper and taillight.

The tunnel and front and rear suspension changes account for a 21-pound weight reduction compared to the ‘09 Nytro MTX. But more importantly, the updates transform the Nytro MTX SE into a serious mountain machine, 4-stroke or not.

The standard version of the 2010 Nytro MTX features the new 11-degree tunnel with shortened running boards, but not the new front and rear suspension, Fox Floats, single-ply track or shallow approach angle. It’s basically the ‘09 Nytro MTX with the new tunnel (and new handgrip warmers and replaceable bearing wheels). Obviously, we’re going to focus on the Nytro MTX SE.

All New And All New

We’ve been supportive skeptics of the 4-stroke mountain segment’s development since the release of the 2005 RX-1 Mountain. We’ve been happy to see the introduction of new technology and the advances made in getting a long-track 4-stroke from where it began in ‘05 to where the Nytro MTX SE is now. But there hasn’t been a time (maybe a little with the ‘06 Apex Mountain) where we have been as impressed with the 4-stroke mountain hardware as we are with the 2010 Nytro. There’s still the weight issue, but this sled is a true mountain sled by any definition.

The changes to the tunnel and running boards allow the chassis to lay into the side of a mountain and stay put. The track, now that the running boards aren’t dragging in the snow and trying to push the chassis back to the downside, can get a better bite of snow. On a side note, the 15-inch Maverick is a great move for this sled.

This improvement in handling makes the Nytro MTX SE roll side to side easier and quicker, so you can steer more with your feet and get a better response out of the sled. That makes the sled easier to ride through trees and transition side to side through drainages.

If a sled is easier to ride, you’ll go farther on it with less fatigue at the end of the day. The Nytro MTX SE is far less exerting on you physically than the previous versions, thanks to reduced weight and a more agile chassis. The sled really likes about two feet of powder on a firm base. Firm snow conditions will bring out the weight factor more than riding it in powder, but the changes to the suspensions still make it a better ride in all conditions.

We first laid eyes on the new Nytro at a press event in Alpine, WY, in early January. The snow had been piling on up high, with cloud cover most of the day. Troy Johnson led a group of nearly a dozen new Nytro MTX SE 153s and 162s into the Alpine backcountry. We left the marked trail as soon as we had crossed the Greys River. We had the advantage of sort of knowing where Johnson was going, so we took every opportunity to jump ahead of the group. We spent the entire ride in untracked snow, dropping into drainages, pulling long, steep climbs with trees and sidehills mixed in. We tried every maneuver we would pull in those conditions on an 800 mountain sled, either to get out of a jam or just to see if we could do it on that sled. There are things we did on the 2010 Nytro MTX SE that we would never have done, tried or gotten out of on the ‘09 model.

We’d hate to say that the Nytro MTX SE handles just like the modern 2-stroke mountain sleds, but that just might be the ultimate compliment.

4-strokes

Comparison chart








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