Now in its third full season of being offered in the REV platform, the Ski-Doo Summit Adrenaline gets even better. Lighter is always better...

Now in its third full season of being offered in the REV platform, the Ski-Doo Summit Adrenaline gets even better. Lighter is always better in the minds of mountain sled riders, and Ski-Doo mountain sled engineers have been looking at ways to reduce the weight of the Summit models while retaining durability and keeping production costs in line. The result of these efforts is an aggressive weight loss program that trims 15 pounds from Summit Adrenaline and Highmark packages, and 20 pounds from X-package and Highmark X-packages.

The biggest weight savings come from the new skis (4.4 lbs), rear suspension (4-5 lbs), seat (4-5 lbs, depending on type), the elimination of the rear heat exchanger (and all of the fluid in it), and a smaller taillight and no rear rack (good for three pounds). They even gun-drilled the countershaft. Highmarks and X package also get 4130 chrome moly a-arms, good for another 3.5 pound reduction in a critical area; the front suspension.

New skis, again. This is one area where the technology, or knowledge, keeps evolving. Ski-Doo was still sorting through the details of their new Pilot 6.9 ski back in March, but what should be “final versions” showed up at our shop about mid-April.

The goal was to make a wider offset mountain ski to improve vehicle flotation without compromising the vehicle width. Each ski weighs in at 5.6 pounds, is 6.9” wide (thus the Pilot 6.9 designation) and is a full 42” long. It uses similar square carbide runners with angled studs as the new Pilot skis on the other 2006 Ski-Doos, and there is no metal bridge to attach to the spindle; the bridge function is now integrated into the plastic.

You’ll also find new seats as part of the diet. This new, simplified seat is found on all of the Summit Adrenaline and Highmark models and weighs 1.3 pounds less than the 2005 version. Summit X and Highmark X models are fitted with the new 440 racing seat.

Under the hood, the Ski-Doo roller secondary clutch is now standard on all Highmark and X packages, providing a major improvement in backshifting – especially when unloading off bumps.

A nylon spacer has been added to the TRA-III drive clutches, this to eliminate any contact between the sheaves at full shift out.

Getting all of the power to the ground is now more efficient with dual 10-tooth heavily reinforced internal/external track drivers. The big benefit here is the significant reduction in rolling resistance. This driver arrangement allows the track to be run with less tension (friction), thus more of the power from the engine ultimately makes it to the track and to the ground, propelling you faster, higher and easier along your way.

Another “quiet” improvement is the fact that all Summits now have “tipped up” rails to increase the speed and reduce the effective track length when on firmer snow conditions. In typical packed trail conditions, this feature can make the sled “feel” shorter than it really is by relieving some of the pressure at the rear of the rails, yet out in the powder the length is all there. A subtle yet noticeable improvement.

One area where Ski-Doo has an advantage is with their wider 16” tracks and larger footprint for each given track length. Two new tracks hammer this home, a 162” x 16” x 2.25” and a 151” x 16” x 2.25”. The 162” x 16” has 2592 square inches of surface area on the snow, where a competitive 166” x 15” track has only 2490 square inches of surface area on the snow. This means you get even more flotation, along with the benefits of a shorter track (wheelbase, tunnel). Maneuverability is better, turn-outs are easier, basically the best of both worlds. Add to this the fact that the added footprint is not simply extra length catching and working the same snow, but added width that captures new and previously untouched (un-compacted) snow, an added advantage.

Ski-Doo is also bringing “relieved” tracks to the OEM world with their lightened Challenger tracks with two holes per bar in the center. Think of a snowshoe and all of the open area and you’ll get the idea. This reduces the rotating mass of the track by another two pounds, which dynamically amounts to an even greater benefit in terms of performance.

Summit Adrenaline and X models are all REV-based, available with a 600 SDI, or new for 2006, a PowerTEK 800 H.O. Riding in the mountains is now cleaner and more fuel-efficient than before, but with no power penalty and only slight weight gains with the added complexity. Bottom line, these 2-strokes automatically adjust for variations in altitude, temperature, and all sorts of conditional changes. About all you need to adjust is the clutching as the elevation changes dramatically, and this often consists of a simple TRA clicker change, with a pin swap at worst. There currently is no sled that makes it easier to go from low elevation to high.

All Rotax 800 H.O. engines now benefit from the PowerTEK engine management system’s higher fuel economy, reduced emissions and crisper throttle response. All engines with PowerTEK exceed 2006-2010 U.S. EPA standards. This electronically-enhanced 800 H.O. made its debut last season on flatland sleds, and is now offered in a higher compression version for the Summits (13.25: 1 vs. 12:1) to compensate for the reduced cranking compression at higher elevations. Power should remain in the 140 HP arena, and with the light weight chassis the performance is about as solid as you can find. Sleds with more power all weigh heavier, making the Summit 800 one of the best deep snow sleds in the biz.

Features include a throttle position sensor, electronic RAVE power valves, a knock (detonation) sensor and an enhanced MPEM “brain box” to crunch all of the new data inputs. This is still a carbureted engine, but riding one you’re hard pressed to know there are carbs under the hood as throttle response and the auto-calibration makes the PowerTEK crisp and clean throughout the powerband.

The Rotax 600 H.O. SDI engine package is now in its third year, and most all of the (minor) development issues have now been taken care of. Power is respectable, but not quite the highest for this class, at about 115 HP. More importantly is the spot-on running quality and consistency, from day to day as well as up and down the mountain. The fully-computerized injection system monitors various sensor inputs and adjusts the engine to perform reliably and efficiently, via multiple outputs; fuel injector timing and duration, ignition timing advance, and exhaust valve timing and positioning. It even monitors and adjusts for detonation, caused by poor fuel or whatever.

Ride Impressions
Last season the Summit models didn’t see many changes, so the upgrades for 2006 are very welcome. The Arctic Cat M-7 sort of put the screws to the weight issue, thus the diet. The Summit REV is where the rider forward ergonomics took root with the mountain riders and is now almost a must-have feature for active and stand-up riding. The difference this makes in terms of agility and quick responsiveness is profound, to the point that it takes some getting used to after riding anything else. With your hips above your knees, you can quickly and easily pop right up off the seat and make whatever maneuver you need to, standing, leaning, whatever, and this makes such a huge difference when boondocking and cutting through unmarked terrain. But, at the end of a long day it would be nice to be able to stretch your legs out and sit back and relax. Shorter riders don’t notice this as much as taller ones do.

The 16″ wide tracks continue to make these sleds float where others struggle. We’re believers in this track design, especially since Yamaha validated the concept by going to a 16” wide track on their new Apex Mountain. It adds measurable flotation for each length and allows you to choose a shorter platform with the same or more footprint than the competition. In most every condition it works better than a 15″ wide track due to the extra inch of snow that its churning.

One thing we used to struggle with is the fuel capacity, as 10 gallons used to be too lean, but with the more efficient engines the tables have now been turned. Usually if a REV is carrying extra fuel, some other sled is using it. Every one of these should carry the trick gas can in a rear rack; every Summit REV needs one. With that said, the Summit Adrenaline 800 H.O. continues to be the most complete and well-rounded mountain sled, and doesn’t leave anything on the table in terms of performance. Big dogs with more power will climb higher, but this one will take you more places with less effort.

With three track lengths to choose from, it is more a matter of how high do you want to go and how deep is the powder. Depending on the conditions, the shorter track lengths are better all-around sleds while the longer ones float better in the deep. Shorter, lighter riders could find the 144” adequate in all conditions. The 600 tends to run out of power at higher elevations, the 800 goes most anywhere. X-models add better shocks and a more aggressive shock package along with better brakes, but are only offered during the spring. Not to worry, the Adrenaline models cost about $500 less and climb just as high.

The 2006 Summit Adrenaline 800 H.O. PowerTEK 144” retails for $9,149 and the 151” at $9,449, and the 144” 600 H.O. goes for $8,399.

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