It made sense to use a 4-post primary clutch for the higher-torque applications. Having four flyweights and towers would make the clutch stronger, and each flyweight could be lighter to provide the same amount of belt squeeze. So, Arctic Cat fitted their Jaguars and F-1000s with a 4-post primary last season.

Not this year. Arctic engineers have deemed they will be able to provide “improved clutch calibrations” by returning to the 3-post primary. While this will require a change in flyweight mass (each flyweight will be heavier) to make up for one less flyweight, the F-1000 also gets a 46/40 helix in the secondary for improved acceleration and performance.

While most of us are aware of the EPA requirements to reduce carbon monoxide and unburned hydrocarbon emissions from snowmobiles starting with the 2006 model year, few have heard of, or are aware of the new “fuel tank permeation” requirements. That’s right. If you’ve removed the gas cap and noticed what looks like a “liner” on the inside of your new sled’s gas tank, this is what we’re talking about.

Seems the EPA wants less fuel to “evaporate” through the fuel tank. Uh huh. As fuel sits in a plastic storage device, the plastic actually “breathes” and allows some fuel vapors to escape into the atmosphere. By using better materials, permeation of fuel through fuel tanks and hoses into the atmosphere will be reduced. The larger benefit to the average snowmobiler is how these changes should noticeably reduce the smell of gasoline coming from your snowmobile. That would be nice.
According to the EPA, the permeation requirement should only cost about $10 per machine, which should be offset by fuel savings.

One solution to this problem is offered by GE Plastics – Xenoy Resins. These new Xenoy resins incorporate an inherent barrier material that provides adequate permeation resistance. In simple terms, use this Xenoy stuff in the plastic as you make the tank and you’re done, instead of having to coat an existing tank. It comes in both blow-molding and injection-molding resin grades, and is expected to be used in fuel tanks for lawn mowers, weed wackers, snow blowers, and most personal recreational vehicles. If you’re into making fuel tanks, visit www.geplastics.com and look for Xenoy resin.

Long-time Arctic Cat riders have correctly pointed out that the new Arctic Cat 800 and 1000 laydown 2-stroke engines are not the first Arctic Cat power plants featuring two spark plugs per cylinder. This feature was also found on some of the Kawasaki-built engines from the early to mid-1970s, but for very different reasons.
Thirty-plus years ago Arctic Cat used the technology to reduce fouling because of the inadequate magneto ignition systems used at the time. Today, ignition systems are far more powerful, and plug fouling is far less frequent and, for all practical purposes, a faded memory.
Improving the fuel efficiency and reducing the engine emissions was the catalyst behind Arctic Cat’s redevelopment of twin-plug technology for the release of the big bore engines in 2007. At lower rpm, there is less turbulence of the fuel/air mixture in engines like the 800 and 1000.
Less mixture turbulence in the combustion chamber results in incomplete burning of the mixture, which means less than ideal fuel economy. By using two spark plugs that fire simultaneously, engineers achieved more complete combustion at low rpm (there is minimal effect at higher rpm because of the greater mixture turbulence). The latest system also incorporates sequential firing, with all of the ignition’s spark energy going to the pair of plugs (and cylinder) that needs it.
Dual sparkplugs per cylinder were just one of the technologies Arctic Cat employed to reduce emissions and improve fuel economy. With tighter emission regulations now only two model years away, look for this trend to continue.

Every year, a number of snowmobilers are surprised to learn how quickly gasoline deteriorates in their snowmobile. Either the sled doesn’t start after a “normal” period of storage, or it won’t idle (or run properly) after coming out of storage, or the sled doesn’t start as soon as it gets cold out.
Here’s why. Gasoline can stay fairly fresh for a while, if stored in a sealed, non-vented container. This is to keep the gasoline’s “light ends” from evaporating. The light ends are what allow the fuel to ignite easily at first start-up when the engine is cold.
A snowmobile’s gas tank and fuel system is vented to the atmosphere, so it is far from sealed. This fact means the gas in your sled is really only “good” for about 30 days in this type of storage medium, an unsealed container. Sleds are usually stored from Spring to late Fall, usually in warm and humid conditions and under wide temperature swings. This is why a sled typically experiences some of the worst fuel-related problems in all of motorsports when the fuel is left in it for extended periods of time.
How does this happen? The tank actually breathes during the wide temperature swings. Light ends evaporate and saturate the air inside the tank. The tank warms, and the air-fuel vapor is pushed outside the tank through the vent. Then the tank cools, and draws back in fresh air. The cycle repeats the next time the fuel warms up, light ends evaporate, saturate the air in the tank, vapor is pushed out the vent as it heats, then fresh air is drawn back in as the tank and gas cools. Slowly, the gas goes “flat”.
This means that keeping the tank full and reducing the temperature swings (store at a stable temperature) will minimize the loss of light ends. Minimize, not eliminate.
The other problem with evaporation of the fuel is crap known as “soluble gum”. When gas evaporates, this is the sticky goo left over that plugs carb jets. It is formed by oxidation of certain hydrocarbons that combine slowly with oxygen in the air and form gum.
Fuel manufacturers are required to contain a deposit-control additive. If the gasoline contains a lot of soluble gum, then the normal amount of additive may not be enough to clean away the left over gum from storage. This is why you might need to treat the first tank of the year with an extra dose of cleaner if a machine displays drivability problems after being stored. From a reactive stand-point, we’ve found a product called “Schaefer’s Neutra” to really do the job when you need to clean the fuel system. A 12 ounce bottle added to 10-12 gallons really makes a difference. Dissolving and removing the gum, varnish and internal residue is where this product shines. It’ll take a lot of the carbon off the power valves as well and out of the combustion chamber, but should be used as an occasional cleaner rather than on an every-tank basis.
From a proactive stance and as a preventative measure, placing a Fitch Fuel Catalyst into the fuel tank will keep the fuel fresher longer, continually “cracking” the longer chain hydrocarbons down into “light ends” so the fuel stays able to easily ignite after periods of storage.

Here is a power and torque graphic for the Genesis 130 FI (fuel-injected three cylinder 1050cc four-stroke) found in the all-new 2008 Yamaha Nytro FX models.
The addition of fuel injection and the increase in displacement yielded a 16-horsepower gain over the Genesis 120 engine it is based on. “We built this engine with an eye squarely on the ISR Stock 600 Class rules”, said Yamaha Snowmobile Product Manager, Adam Sylvester. “We wanted the new engine to be fast-revving and powerful for both competition and for consumers. We got everything we had hoped.”
Yamaha brought a preproduction Genesis 130FI engine and a full-production Genesis 120 engine to (our old friend Olav Aaen) at Aaen Performance’s dyno testing facility for same-day, back-to-back testing in order to determine the extent of the performance difference.
Peak horsepower figures were 138.6 HP on the FX Nytro and 122.6 HP RS Vector. Both engines showed a very similar curve profile, holding their respective peaks for several hundred rpm.
Torque showed a similar gain, from the carbed 120 to the fuel-injected 130. The Vector engine showed a peak torque figure of 82.9 foot/pounds. The FX Nytro
engine pulled 94 foot/pounds at 7100 rpm. “That kind of torque is near what consumers have found in competitive big-bore 2-stroke engines in the past,” said Yamaha Snowmobile Marketing Manager, Rob Powers.
The Genesis 130FI engine also showed a huge gain in torque down in the low end. At 3500 rpm, the new engine posted nearly 72 foot/pounds of torque. That is a 17-point improvement over the Genesis 120 engine. “Consumers are going to absolutely love the high torque this engine puts out at clutch engagement,” added Sylvester. “The reason is this engine’s amazing low-end grunt.”
The torque curve is what you feel when you squeeze the throttle. The new fuel-injected triple comes alive quickly and with authority, delivering a wide torque delivery all the way from a grunting 5000 RPM, rising quickly and peaking at about 95 pound-feet of torque at around 6,000 RPM, remaining strong through the entire operating range.

One of the false stereotypes our industry continues to fight is that of noise. The occasional piped-sled with open stingers or burnt-out packing in their mufflers makes non-snowmobilers think that all snowmobiles are this loud, but we all know that to not be true.
Nationwide, there is a backlash against loud recreational vehicles. This includes resentment against the sharp increase in loud motorcycles. Riders install loud “pipes” on their street bikes, and produce noise levels that far exceed that of snowmobiles. Law enforcement agencies and legislators are hearing from the populace that “enough is enough”. So why all of the attention with snowmobile noise when motorcycles are so much louder?
Nowhere is this “double-standard” more evident than in Yellowstone National Park. While snowmobiles can not enter the park unless they meet noise regulations that are far more stringent than for the rest of North America, loud motorcycles pull into the park relatively unchecked and unrestricted. So, how is that fair? It isn’t.
All new snowmobiles are manufactured to pass two intense sound test procedures. They are certified by a third-party, internationally-recognized testing agency which administers the two rigid sound tests. First is the SAE J-1161, which is a steady-speed pass-by test, and the second is the SAE J-192, which tests the vehicle in the most extreme operation condition; wide-open throttle acceleration.
When following the SAE J-1161 test procedure, the machine can generate no more than 73 decibels at the steady speed of 15 mph. When following the SAE J-192 test procedure, the machines at full throttle can generate no more than 78 decibels at a distance of fifty feet, with a 2 dB allowance afforded for variances in environmental conditions. So, in effect, 80 dB at fifty feet is as loud as a “certified” stock sled can ever be when measured at fifty feet. Remember, this is at FULL THROTTLE.
Curiously, many road vehicles emit a higher amount of noise than snowmobiles when the J-192 procedure is followed. Some vehicles, like trucks and motorcycles, were measured at levels up to SIX TIMES the legal limit for snowmobiles. Again, a double standard?
The SAE, working with other government agencies, has recently developed a special “in-field” test procedure titled SAE J-2567. This procedure is aimed at allowing enforcement officers to test a machine in a stationary position. The most important thing to remember is that a noise limit should be applied equally and fairly across the board. None of this lifting the hood and declaring a sled in violation simply because a modification has been made. Stock or not, each sled should be subjected to the test without bias, and if it passes, so be it. If it fails, so be it. Because, a good number of sleds that were supposedly “compliant” at the time of their manufacture are no longer in compliance due to deterioration of their mufflers. And, a number of “modified” sleds will prove to be as quiet, and quieter, than some of the stock sleds.
The bottom line here is to eliminate the truly loud snowmobiles from the public trail system, which causes user conflicts and ultimately is used against us in land closures and access issues. Loud sleds have no place on the trails of 2008, and now enforcement agencies have a legal method of keeping the noise to an enforceable limit.
It is only a matter of time before this same principle is applied to the loud motorcycles that are disrupting the highways across North America. An exhaust that rumbles is one thing; outright loud and obnoxious machines are simply rude and demonstrate disrespect for the privilege to ride.

Mountain riders have discovered the Arctic Cat M-Series sleds can over tension the track as the suspension goes through its travel. For this reason, many riders have resorted to running their tracks looser than they feel comfortable with.

While many will install extrovert drivers to help deal with this problem, a geometry revision is helpful to cure the root problem; inconsistent track tension as the suspension goes through its travel cycle.

One of the most popular options to help this problem is to install the “M7 Front Torque Arm Relocation Kit” from Holz Racing in Lynden, WA. www.holzracingproducts.com. This innovative ($69.95) kit fixes the track tensioning problem on stock M7 rear suspensions so the suspension can cycle freely without the track over-tightening. This, of course, frees up horsepower and improves the ride quality. Most owners have found this to be a “must have” for an M7!

If you ever have the need to remove carbon from aluminum engine parts (like power valves) here is a product we ran across being used in the automotive world and with ultra-lite aircraft. It’s called “Piston Kleen”. It sells for only $8 per gallon and is available from Orison Marketing, manufacturer and distributor of industrial strength cleaners.
Piston Kleen is marketed as a safe, effective, and economical water-based cleaner engineered to remove baked-on carbon, oils, greases and other soils from tracked vehicles (that’s us), trucks and automotive engine parts. Developed to remove burnt-on carbon deposit in the piston rings on U.S. Army vehicles, Piston Kleen makes easy work of a major problem. Piston Kleen is recommended for soak tanks, cabinet washers, ultra sonics, and through-put machines.

Simply soak the piston/parts in Piston Kleen for 2 to 24 hours to remove even the nastiest build-up. Agitation and heat decrease the soak time, but is not necessary. Orison recommends agitation with a working temperature of 900 to 1800 F.

To get some visit www.orisonmarketing.com. They also have a host of other bio-safe cleaners, rust inhibitors, and interesting products developed for military and industrial applications.

SnowTech reader Charlie Herber is passionate about snowmobiles; orange Moto-Skis, to be more precise. After doing some damage to his current sled last year on a late winter ride, he got on the net looking for parts, which led to looking at sleds. This is how he found a 2005 Ski Doo GSX Fan for sale at a great price.

After looking at the sled, Herber wondered if it was so cheap because it wasn’t that great looking in the graphics department. He bought it, thinking he could jazz it up.

After looking for some used accessories, he discovered a lot of orange body pieces were available. This brought about the realization of creating his own Moto-Ski REV, a custom sled that not only worked well but looked very unique. He started picking up parts here and there, but it still needed more. Herber talked to a friend who is a graphic installer, and he jumped at the chance. Besides, he owed him a favor.

Herber dropped off the sled and gave him a picture of an old Moto Ski and told him to use his imagination on what they would look like today if they were still being built. Herber showed up a few days later and absolutely loved it.

There are no indications of it being a Ski Doo, except the name on the skid plate. Herber hasn’t been able to drive it much due to little ride-able snow in his area this year (SE MN). When it’s sitting in his front yard he has gotten a lot of people rubber-necking as they drove by. Imagine their disappointment when they try to locate the nearest Moto-Ski dealer!

What do you do if your sled has a terrible “track howl”? This isn’t something that just shows up, it is with the sled from day one. Normally, the track will howl quite loudly at a very specific speed, yet makes much less noise at speeds above and below this. It is caused by a resonant frequency of the track at a certain speed range, and riding the sled at this speed is very annoying.

Two recent examples include the 2005 Yamaha RS Venture and the 2006 Polaris Classic 700. Some of these models will howl at speeds around 40-60 mph.

We don’t have a quick fix for this one; things riders have tried include verifying proper track tension, replacing plastic idlers with rubber wheels, varying approach angles, and ultimately installing a different track. Any one with suggestions, send them in!