Looking At Snowmobiles Under The Microscope

The Yamaha Phazer FX, Polaris FST IQ and Ski-Doo MX Z 800 H.O. Blizzard were closely examined last spring in the Snow Goer laboratory at our Rode Reports test event in Munising, Michigan. The concept behind Under The Microscope is to take an in-depth look at snowmobiles that don’t necessarily compare to each other. We tested the Arctic Cat F8 separately.

The all-new Phazer FX is an altogether new approach at building a snowmobile. The company hopes to attract new people to the sport and invigorate experienced riders into buying a fun, sporty sled. If a sled is desired to help people feel like a kid again, the Phazer is their candy store.Trail riders who want the convenience and smooth power of a four-stroke but also want to hit the trail hard and not risk their hard-charging image owe it to themselves to consider the FST IQ. Don’t worry, Mr. Middle-Aged Ricky Racer. Your hard-charging image is safe here.

The MX Z 800 H.O. Blizzard from Ski-Doo is for snowmobilers who want good ol’ two-stroke power and a nearly flawless chassis. This sled is a can’t-go-wrong package powered by the intoxicating 800 H.O. PowerTEK engine.

Phantastically Phun Phazer FX
Aaahhh … a birthday during childhood. That day every year is the most fun for a kid. Whether it’s because the school day is interrupted by a classroom celebration with sugary treats or the party later that day with friends, presents and cake, nothing pegs the fun meter for children more than the day to mark their arrival on this flying dirtball we call Earth.

Now that youth is nothing but a memory, Mr. 30-something, and birthdays are simply a reminder of how fast you used to be, you need a way to feel like a kid again. Thankfully, Yamaha has a solution: the new Phazer FX.

Available in red or blue and standard with push-button reverse to save your aging bones for riding — not unloading — the Phazer FX was one of the most fun and the most surprising sled at Rode Reports in Munising, Michigan, last spring. Its engine surprised us and its chassis and suspensions are the best in the bumps this season from the Japan-based manufacturer.

Cool, New Chassis
The Phazer FX’s goodness starts with its foundation. The machine is built on the FX chassis that Yamaha labels sport rider-forward. Compared to the Nytro, one of the company’s other “rough-trail” sleds, the Phazer’s seat and handlebars are taller, farther forward and closer together.

Ergos of the machine are set up for either taking it easy or hitting the trail hard. The perch of the handlebars, their width, the grips with hooks, the seat’s firmness and its height worked well.

Right and left chassis components are fabricated via controlled-flow die cast technology. Material is forced under pressure into a cavity to create the part. This technology eliminates air bubbles that would otherwise form in the aluminum. With the air pockets gone, parts are more dense and stronger, which enables engineers to make them thinner and lighter. A cool aspect of the chassis is its integrated chaincase.

This component is cast into the right frame member to reduce weight and complexity and improve the rigidity of the drivetrain, which should improve efficiency and reliability. The cover is made of lightweight magnesium.

Another component of the chassis is its chromoly bulkhead to which the aforementioned cast aluminum parts, cooling extrusion and engine attach. The tunnel is made from stamped aluminum. It’s open on the top side to allow snow to cool the exhaust pipe.

Updated, Better Suspensions
Laughs and smiles were abound when we rode the Phazer FX through rugged sections of tight, twisty trail in the woods of Northern Michigan. The sled felt nimble, which made it easy to control.

We were as happy as boys at a county fair with a snowcone in one hand and a cap gun in the other. Fun was had because this Yamaha is fitted with new suspensions that are well-suited to active, spirited riding. The double wishbone front end has 10 inches of travel and aluminum, high-pressure gas, piggyback shocks with clickers that affect compression and rebound damping.

The A-arm suspension is different than that used on Yamaha’s other sleds. A-arms are parallel on Apex, Nytro and other trail sleds, but the FX chassis’ control arms are about .5 inch farther apart at the bulkhead than at the spindle. This translates to better big-bump capability, flatter cornering and improved straightline tracking. Instead of traditional post-style spindles, the FX’s are made of extruded-aluminum, à là Ski-Doo REV.

Out back, the Phazer FX has the second-generation Pro Active skidframe. Unlike the Nytro’s Pro Active skid, this new version has coupling blocks rather than control rods to affect weight transfer and suspension action. Other sled manufacturers have used this general design principle for more than 10 years, in some cases.

The front track shock is an aluminum, high-pressure gas damper. The rear shock is a compression adjustable, piggyback clicker. Both shocks are made by KYB. Rear travel is listed at 16.1 inches.

Genesis 80FI
Yamaha is the industry leader of four-stroke snowmobile engines. The Genesis Extreme was launched for 2003 and upgraded to the Genesis 150FI for 2006. The middleweight 120 hp three-cylinder that’s used in several models debuted in 2005. Now, the all-new Phazer is home to the first small-bore four-stroke snowmobile engine.

To build it, Yamaha took its YZ250F off-road motorcycle engine, added another cylinder to double its displacement and installed fuel injection. The finished product is the all-new 80FI; it brings a half-liter of fun to the Phazer. The engine’s bore and stroke is 77 by 53.6mm, which is the same as the 250F powerplant. Electric start is standard.


Unlike the dirtbike’s engine, though, the 500 uses a pair of 43mm Keihin throttle bodies to deliver fuel. A five-valve head caps the monoblock cylinder. Yamaha claims it puts out 80 hp. Maximum power comes on at about 11,250 rpm, but gear reduction brings clutch speed down to a less dizzying 8500 rpm at wide-open throttle, which makes the clutches more efficient and easier to tune.
Exhaust is shot through a rear-exit, 2-into-1 system. The single pipe is tucked under the seat where it’s exposed to snow that helps it stay cool and be more efficient, according to Yamaha.

The 80FI is calibrated to run on fuel rated at least 91 octane. Without premium fuel, the engine will lose up to 4 hp. Don’t fret if good gas isn’t available. The engine is equipped with a Knock Control System (KCS), to prevent detonation.

Cooling is mostly handled by a single heat exchanger mounted in front of the track. In addition to the exchanger, a fan-cooled radiator is mounted near the chaincase. This helps the engine run at a consistent temperature, which is especially important for fuel-injected engines.
To help reduce output of vibration from the twin-cylinder engine, it’s fitted with a gear-driven counterbalancer. The second and third lobes of the crank are thinner than the first and fourth pork chops to reduce weight.

Behind the Phazer FX’s handle bars
Power delivery from the prototype Genesis 80FI-powered Phazers we rode last spring was smooth, consistent and enough to move the machine along at more than 80 mph for most riders.

Its pull near wide-open throttle was surprising, especially considering that it’s a small-bore four-stroke. Cruising at about 65 mph then stabbing the throttle flipper to the handlebar made the machine accelerate up to max speed quicker than expected. Vibration came in at high rpm, but this is expected from a parallel twin four-stroke.

The engine’s sound is reminiscent of a sport-class all-terrain vehicle, which makes sense given this engine’s motocross foundation.
The Phazer FX was the easiest Yamaha to manage in the bumps — undoubtedly due to its new rear suspension and lighter weight. The coupler-block-controlled skidframe transferred weight appropriately but also offered more control and stability through the rough stuff than Yamaha’s transfer rod-based Pro Active suspension.

The front end’s longer, unparallel A-arms seemed to handle big hits better, too. The sled was predictable and was usually prepared for the next bump we threw at it.

Though the suspensions are improved, we felt body roll through corners and in some especially rough areas. Our sample sled was a prototype, and suspension calibrations hadn’t been set for production. Hopefully more tuning will eliminate the sled’s roly-poly feel.
Ergonomics of its “sport rider-forward” chassis were right on for active riders. Handlebars were perched high enough to provide good leverage but low enough so the sled could be aggressively driven through corners.

The seat was firm and square, much like a dirtbike. Its square shape near the cowling was too high for small riders to lean into a turn.

Corporations work hard to establish an image. Some companies are perceived well by consumers, whereas others have earned a not-so-shiny image. Honda is known to build quality automobiles. Kmart has cemented itself as a retailer of cheap products by, well, retailing cheap products. Snowmobiles and their riders have images to uphold, too.

Polaris introduced its FST engine for 2006, and it failed to earn high-performance status among aggressive trail riders. The only short-track, turbo-boosted model available was the conservatively dressed FST Classic, which was targeted toward 50-something, groomed-trail riders.

Though the FST was a hot-rod powerplant then, no one knew because it wasn’t packaged as such. Its image packed as much excitement as a toothbrush. Four-stroke buyers whose self-perceived image was that of an aggressive, performance-oriented enthusiast didn’t have an option from Polaris. That has changed for 2007.

The new FST IQ has the high-performance look and feel to attract riders who want a four-stroke but not the image of a 1-Up sightseer. Its available Nuclear Sunset paint scheme, short windshield, handlebar hooks, stout suspension calibrations and firm seat give it the attitude and the feel of a truly high-performance sled.

FST Engine
Before 2003, many snowmobilers scoffed at the idea of a four-stroke-powered sled. But when Yamaha introduced its RX-1, the engine type quickly gained acceptance as a means to power a high-performance snowmobile.

Polaris played the four-stroke game early on with its Frontier, but its performance was anything but high and the model was axed after model year 2005. Now the company has a legitimate engine with its Four-Stroke Turbo (FST).

The FST debuted in several 2006 models. It’s a 749cc twin-cylinder, four-stroke engine with a Bosch multi-port fuel injection system with dual 39mm throttle bodies. The engine is built by the Germany-based Weber company.

Polaris lists the four-valve-per-cylinder, liquid-cooled powerplant at 140 hp for 2007, which is a few more horses compared to last year. Polaris Snowmobile Product Manager Michael Erickson said the company undersold the FST’s output last year and EFI recalibrations helped it gain power. Peak power is made at 7800 rpm.

Unlike the engines in pickups and SUVs that will tow FST IQs to trailheads across the Snowbelt, this four-stroke is a dry-sump design that stores and pumps oil from a reservoir rather than the crankcase.

This design allows a lower placement into the chassis and easier turnover at cold temperatures. Another advantage is that damage is less likely to occur if the sled is tipped and the engine continues to run. A disadvantage of its placement is that at least one should-be-easy service requires a master’s degree in engineering and a minor in contortionism and strategic thinking.

If a person wants to quickly change a spark plug, or, more likely, check for spark while on the trail; forget about it. Access to the FST’s spark plugs is minimal, at best, because they’re buried under the cowling and in front of the fuel tank. Spark plugs can’t be serviced without tools and a fair amount of disassembly.

The FST has a 360-degree crankshaft, which means both pistons arrive at top dead center (TDC) at the same time. To make the engine run smoothly, it’s equipped with a counterbalancer.

A 360-degree crankshaft needs a counterblancer to negate vibrations that are inherent with even-firing engines. Traditional four-stroke engines that don’t simultaneously arrive at TDC don’t usually require a counterbalancer because their power strokes, which happen opposite of each other, cancel most vibration.

2-Stroke Chassis, 4-Stroke Power
Each manufacturer takes a different approach to build its sleds. Yamaha prides itself for re-engineering its snowmobile chassis to house four-stroke engines. But unlike what Yamaha did to build its four-stroke-powered sleds, Polaris engineers essentially dropped the FST engine into a chassis that was designed for a two-stroke powerplant.

The IQ front end has 10 inches of travel. A set of Ryde FX gas shocks with single rate, coil-over springs dampens the bumps. The torsion spring IQ skidframe has 13.9 inches of travel with a Ryde FX front track shock and a Fox position sensitive damper on the rear torque arm.
Though the FST IQ shares suspension packages with its 600cc, short-track stablemates, it gets Rider Select steering instead of the fixed handlebar. Drivers can choose from the sedate No. 1 position to the aggressive No. 7. The feature was yanked from other high-performance Polaris sleds for 2007.

Heavy steering has been a drawback of the IQ chassis since its introduction in 2005. But updates to the front end for 2007 have made a great improvement in steering effort.

The ski’s bolt hole was moved rearward and down .75 inch, which puts more of the ski ahead of the spindle and lightens the steering effort. To also help achieve a lighter feel, the rear of the keel was shaved. A softer ski rubber between the spindle and ski saddle reduces tail pressure even further.

Behind the FST IQ’s handle bars
The FST IQ handles the high-speed bumps, holes, twists and turns like an aggressive rider would want it to and it has enough power to satisfy anyone who feels the need to experience speed-induced tunnel vision.

The 583-pound sled is well-balanced and performs remarkably well in the rough. It flies flat and straight and handles off-camber bumps as steady as a Caterpillar D9 tractor.

Performance and acceleration is on par with big-bore two strokes. An acceleration chart supplied by Polaris shows that its rate is identical to that of the discontinued 900 Liberty. Our own tests proved that it rips solid holeshots. The FST IQ ran dead even with an 800 H.O. PowerTEK-powered Ski-Doo MX Z up to about 70 mph. Blasting from corner to corner was just that — a blast.

Power came on strong and it turned off seamlessly. Turbo lag isn’t an issue with this engine. On deceleration, we expected to feel four-stroke engine braking, but it was a non-issue. Though its performance is a hoot, its sound is subdued as a grey-horned owl.

No matter how hard we pushed the FST IQ, the engine didn’t sound like it was working hard. It just churned along without, unfortunately, the right kind of noise to make the trip even more exhilarating. “Industrial” is the best way to describe it.

Handling was predictable because the sled cornered flat and stayed on track. The chassis never made a surprising tip or bobble. High grades for handling are due in part to its low-tucked and well-packaged twin-cylinder engine, but positive remarks are mostly due to the IQ chassis. Ergonomics played a role, too.

The sled feels much like Polaris’ other performance sled: the 600 HO IQ. Its firm, tall seat and hooked, Rider Select handlebars let a driver tackle sharp curves or stand up over moguls.

Consequence-free MX Z 800 H.O. Blizzard
Titanic captain Edward J. Smith ignored iceberg warnings during the ship’s maiden voyage. Hours later the luxury liner sunk to the bottom of the Atlantic Ocean.

Howard Dean’s infamous “Dean Scream” at the 2004 Iowa Democratic caucus was a mistake that ended his U.S. presidential campaign faster than senator John Kerry can screw up a joke. New Coke was a flat-out marketing blunder.

Those mistakes were the result of decisions based on arrogance, ignorance or plain-old stupidity. Severe consequences were the result in some of those cases.

Though the determination of which snowmobile to buy isn’t a life-or-death decision, it’s an important one. The decision to buy an MX Z 800 H.O. Blizzard is one that certainly can’t be considered an error in judgement by anyone — no matter what brand they ride. This sled flat-out works.

Legend Of The REV
The MX Z Blizzard is built on the industry-changing REV chassis. In its fifth year of production, Ski-Doo has it nailed in terms of ride quality, comfort and handling. REVs feel solid and strong and the chassis doesn’t flex or twist through the bumps.

Another sign of Ski-Doo’s industry-leading quality initiative is a REV’s serviceability. The chaincase, for example, slides off and on of its three mount bolts without having to pull, pry or twist other parts out of the way. Parts simply line up because they’ve been carefully engineered.

Look under the hood and behind the side panels of a few-years-old Ski-Doo. Chances are it’s clean in there because the exhaust and chaincase gaskets don’t leak. Fasteners and other metal parts will probably be corrosion free because they’re made of high-quality materials.

The SC-4 skidframe was installed in aggressive “X” models in 2005, but that package was only available as part of Ski-Doo’s spring sales program. The chassis was updated last year to increase its stability and help it corner flatter. Other changes last year included new Pilot skis to replace the Precisions and the SC-4 skid was bolted in all versions.

For 2007, Ski-Doo markets its new Blizzard package toward experienced, aggressive riders who want a race-inspired sled. The most significant upgrade over the Adrenaline package — the former full-season, aggressive MX Z — is its shock package.

Other Blizzard upgrades include the HPV roller secondary clutch, steel-braided brake lines and internal/external sprockets on the driveshaft. Color options include Ski-Doo’s traditional yellow/black or new black with white. The sled is also available with the fuel-sipping 600 H.O. SDI powerplant.

Adjustable Front End
Shocks set apart the Blizzard package from the rest of Ski-Doo’s MX Z lineup. Most importantly, the front end is equipped with KYB high-pressure gas clicker shocks. The dampers are bolted in the REV’s Response Angle Suspension.

The steel-bodied shocks have seven positions for riders to choose the best setting for their weight and riding style. The fact there’s only seven clicks is what makes the shocks so great. Some other high-performance, externally adjustable snowmobile shocks have more than 20 clicks.

Adjustability is nice to have, but too much of a good thing will confuse some owners. They become intimidated with so many settings that they’re scared to work with the shocks and really dial them in for the best ride. Can an average snowmobiler even notice the difference between click No. 15 and 16?

Riders will appreciate the adjustability of these HPG shocks. Adjustments are easy to make with a screwdriver included in the tool kit. Each click is firm and definitive. Unfortunately the shocks aren’t rebuildable.

KYB dampers and their components are among the best in terms of quality. But whether the sled is ridden for one year by an aggressive rider or three years by a moderate driver, its abililty to dampen bumps is almost certain to be compromised, regardless of how well the shock is built. Usage causes oil to break down. Airborne rocks and debris can cause damage if it strikes a shaft, which tears up seals that are supposed to prevent shock oil contamination.

Unless an owner rides in a vacuum, free of anomalies that could cause damage or wear, like-new ride quality won’t be preserved. When a person takes into account the $9,799 that’s required to buy this sled, he or she should have the opportunity to retain the best ride quality without having to buy new shocks. The rear-to-front coupled SC-4 skidframe has steel HPG shocks, too. The front arm has a non-rebuildable damper; the rear is serviceable. (Audible golf clap.)

800 H.O. PowerTEK
MX Z buyers have had the option of an 800cc, twin-cylinder engine since model year 2000. The engine has been altogether re-designed since then, and PowerTEK was added in 2006, which made the engine cleaner, stronger and more reliable. It’s one of the finest engines in snowmobiling.

“TEK” stands for throttle-position sensor (TPS), eRAVE variable exhaust valves and a knock sensor, which protects the engine from damage caused by detonation. All of these parts work in harmony to help the 799cc engine run strong, smooth and consistent.

The TPS tells the Multi-Purpose Electronics Module (MPEM) what the driver wants the engine to do — such as speed up. Data from several sensors is collected and crunched, then engine operation is modified accordingly.

Input variables that are collected include air temperature, coolant temperature, vibrations detected by the knock sensor, engine rpm, crankshaft position, barometric pressure and the throttle’s setting. Then the MPEM adjusts output variables: ignition timing, exhaust valve height and fuel supply from the 40mm Mikuni flat-slide carburetors.

Behind the MX Z 800 H.O. Blizzard’s handle bars
The MX Z 800 Blizzard performed as expected on test rides last spring. Due to its external adjustability, this suspension package will be almost perfect for 95 percent of its owners. Why won’t it be “just right” for everyone? Nothing’s perfect.

We’ve become more familiar with the chassis’ characteristics — both good and bad — after riding it since 2002. The Blizzard’s personality through smooth to moderately rough corners was calm and cool. It carved smooth and flat through tight, twisty sections of trail that weren’t whooped out.

Through fast, rough corners, the chassis suffered from bump steer and body roll. It’s twitchy. This has become even more evident since Polaris’ IQ raised the bar for front suspension performance.

When a REV’s skis leave the ground, they wash back and forth and the body rolls. The machine stays controllable because the RAS front end and SC-4 rear are more forgiving than Lord Jesus Christ (sorry, Father), but this keeps an aggressive driver busy and contributes to fatigue.

The package offers seamless, uninterrupted power whether the trail is smooth or rough. For comparison, we’ve experienced quick lapses in fuel delivery from the SDI-equipped 600 H.O. engine in rough conditions at a fast pace.

As a whole, the 800 H.O. PowerTEK is a strong, well-running, fuel-efficient engine. A squeeze of the throttle at any rpm yields smooth and strong acceleration that’s like the perfect drug. The power-high is addictive but lacks consequence.

Once something is invented, it can’t be re-invented. But in the case of Arctic Cat’s F-Series, “re-invented” is the only term that does the sled justice. The only thing that’s been carried over from the original version is the name.

The new F8 is a well-handling, smooth and stable chassis with an engine that, according to initial impressions, offers great trail power.

Twin Spar Chassis — Twice As Good
Rigidity, rigidity, rigidity. That’s the message Arctic Cat pounded home last spring when it introduced the Twin Spar chassis. The company claims a new F-Series machine is 46 percent more torsionally rigid than the Firecat chassis it replaced.

A rigid frame translates to sharp handling and a tight, predictable feel. Suspensions can be calibrated more accurately because engineers have fewer variables (chassis flex) to account for as the suspensions move through their travel.

The Twin Spar chassis feels tighter because there’s less body roll and slop when the machine is pushed through a rough turn. Instead of twisting, the chassis stays flat and true to itself from front to rear while the suspensions soak up the junk.

The Slide Action skidframe is unique because it maintains near full travel at the front torque arm when under acceleration. When a driver hits the gas to accelerate out of a corner, for example, the Slide Action suspension shifts back. The front torque arm of typical coupled suspensions will compress under these circumstances.

The new AWS VII front end starts with a machined sub-frame manufactured to tighter tolerances. Like the rest of the chassis, new forged shock towers and spindles are more rigid. The steering post is mounted to a solid roller bearing for light steering.

800 EFI Laydown
Compared to Cat’s laydown 700, the 145 hp 800 has six percent more torque at wide-open throttle and 26 percent more torque at 6000 rpm, which is the range where the engine spins at mid-range throttle position (read: power to get from corner to corner).

The 800 engine’s bore and stroke is 85mm by 70mm; the F7 and F6 powerplants also have a 70mm stroke. The 800 uses dual, 46mm throttle bodies and has a knock sensor to help prevent detonation caused by bad fuel.

The new 800 engine is a twin-cylinder design, but it has dual spark plugs for each hole. Cat claims this results in a better burn for more complete fuel combustion at low- and mid-range throttle settings.

When poking around under the hood of a new F8, take a look at its recoil. It’s big! Cat did this to give more torque to the person who pulls the rope, which makes it easier to turn over. Cat still guarantees two-pull starts with the engine.

Behind the F8’s handle bars
Our ride impressions of the new F8 are based on two days of test rides last spring near West Yellowstone, Montana, where trails start at about 6,500 feet above sea level. The sleds were prototypes and fuel and clutch calibrations were not finalized.

The new engine seemed to have a broader powerband than the 140 hp 700 engine it replaces. The 800 boasts only a 5 hp gain over the 700, but it had better power that was more trail friendly.

Even though we were at elevation, power seemed broader between turns and acceleration out of corners was stronger. Mid-range punch also felt meatier than Arctic Cat’s original laydown engines.

Chassis and suspension performance was definitely better than that of the narrow-track F-Series. The new supensions and chassis had more control and a more settled-in feel over rough terrain. Handling was sharp and ski lift was a non-issue.

Aside from its outstanding control, steering effort was light enough to make us wonder whether the front end would stick to the ground, but it did. Turns were effortless and the sled railed through curves without a hint of losing grip.

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