December 31, 2007
Just like all of the other 2008 MX Z models, the all-new MX Z Renegade gets what amounts to the most comprehensive make-over ever when it comes to a snowmobile re-design with the REV-XP platform. About all that’s left over from last year are the engines, primary clutch, skis and coupler blocks. That’s it. Most every other part and piece on the Renegade is all-new. The REV made history, and the REV-XP has the potential to be even bigger.
With this much re-design, it’s hard to know what to expect from such a radically different sled. Instead of a 136†track length, the Renegades now come with a 137†track length. The number of bars is the same, but with slightly longer spacing between them the length stretches out slightly.
The biggest difference, of course, is the weight reduction. Figure fifty pounds lighter across the board, regardless of engine size. This translates to quicker acceleration, less fatigue after long rides, increased maneuverability, and a sled that simply brings back memories of the smaller, lighter sleds of the past. But, with new suspensions and clean two-stroke motors. What remains to be seen is if the rear suspension performance and engine vibration (800R) has been improved over the early prototypes.
The MX Z Renegades continue their tradition of being the better choice for those who enjoy true cross-country riding, a mix of groomed trails and off-trail riding. The added length keeps the tail in line, adds flotation, and smoothes the ride quality with the longer wheelbase. Only in the tightest and narrowest trails will you notice the added length, to the point you might wonder why sleds with shorter tracks are even made. As far as we’re concerned, the Renegade has THE track length that suits more riders more often.
The MX Z Renegade has a choice of two premium engines, each with class-leading power, crisp, linear acceleration, incredible fuel economy and U.S. EPA certification; the Rotax 2-TEC 800R PowerTEK delivers 152 HP, with the 2-TEC 600 H.O. SDI rated at 118 HP. Both engines give the Renegade the lightweight handling of a two-stroke with the fuel economy and emissions as good as, or better than, a four-stroke. Weight? 430 pounds for the six, 437 for the eight. We’re talking 2.875 pounds per horsepower…….did you catch that?
The 2007 Ski-Doo MX Z Renegade 800 H.O. PowerTEK sells for $9,949, and the 600 H.O. SDI goes for $9,049. Buyers in the Spring could also opt for the X-package option, with high end shocks and more race-sled features along with a low windshield and handguards.
December 20, 2007
That’s right, a plastic rear suspension from AD Boivin, makers of the SnowHawk “snow bike†and the Expert X rear suspension. Called the ZX2 , the rails and swingarms are all made of a plastic composite material, said to be very robust, very durable and free of “weldingsâ€.
The swingarms and wheels (including four 8 in. (200 mm) wheels on the rear axle) are made from UHMW polyethylene (just like plastic skis), and the rails are made from a very special UHMW composite, with both plastics coming from PPD in Sherbrooke, Quebec.
AD Boivin also indicates the composite construction acts much like a plastic ski in that it has the unique ability to absorb vibrations and improve the ride experience. The composite is also permitting a certain flex on bigger bumps and turns, helping eliminate bad feedbacks to the rider.
Available in five different colors (black, yellow, red, blue and green), the ZX2 will certainly provide a unique and modern look to your sled. Depending on its length, the weight (ready to install) varies between 53 and 56 pounds, which represents a weight saving up to 20 pounds for certain models, and is said to be the lightest aftermarket snowmobile suspension available. It is also claimed to have 50% fewer parts than any other suspension on the market. While AD Boivin’s Expert suspension has 152 parts, there are only 51 parts on the ZX2. Of those 51 parts, 12 are identical bolts.
SnowTech test riders have not been given the chance to ride this latest version of the composite rear suspension, but did evaluate an early prototype several years ago. Denis Boivin came up with the idea back in 1998 and has been working on it, on and off, ever since.
Of interest is the fact this is a two-arm suspension, not a single swing arm like the Expert and Expert X suspension. Curiously, both of the shocks are located side-by-side on the rear arm, with no shock at all on the front arm! This arrangement is likely to afford a great amount of ride quality, with the front arm linked to the rear arm (coupled) to keep it from bottoming harshly. There is, however, a limiter strap on the front arm.
One unique feature is the “Revolver†quick-adjust system, which allows you to quickly and easily change the shock leverage ratio for weight transfer and ride comfort adjustments. The plate at the rear of the suspension has five holes and two pins. Two of the holes are for a weight transfer adjustment; the other three vary the moment of “coupling†between the front and rear swing arms.
Spring preload on the two rear shocks is adjusted using an included wrench in the openings on each rail to reach the preload ring (7 positions) of the springs.
The ZX2 includes two KYB shock absorbers that have a positive sensitive system called “G-Force†technology. This custom valving provides a real dual-behavior to offer comfort for the majority of the ride and an anti-bottoming zone for more security and to suit aggressive rider needs. The first 75% of the shock stroke is comfy, with the remaining 25% of the stroke reserved for anti-bottoming.
AD Boivin also indicates the ZX2 does not require lubrication (grease) like other suspensions, as the composite material has the unique ability to lubricate itself. Another slick feature is that snow won’t stick to or build-up on the composite parts, either.
Pricing for the composite ZX2 starts at $1,199 for a black 121†version, and $50 more for colored ones. The pricing goes up for the longer-track suspensions, to $1,349 for black and $1,399 for colored, all the way up to 162†mountain sleds. You also have to buy the appropriate mounting kit that fits your model, or buy the universal kit at $149. For more details go to www.adboivin.com.
December 17, 2007
The 2007 Arctic Cat F-Series models have plastic hood screens that are press-fit into the hood at various points; as snow screens up on the front and nose of the sled, and what we call the “knee ventsâ€. During aggressive riding, your knees can contact and knock the screens through the hood, causing them to drop down into the pan of the sled. If you catch them quick enough, you can get them before the secondary clutch (left side) or brake disc (right side) starts to notch the plastic.
The snow screens in the hood don’t seem to come dislodged as often, but busting through some healthy snow you can knock them loose as well. We’ve resorted to trying some silicone glue (sealer) to keep the plastic vents screens in place. If you have to order replacement pieces, be aware that some models use grey ones and some have black ones, so there are a couple different part numbers for each piece. We’ve heard Arctic Cat has changed the vents for the 2008s, with an improved locking design with longer tab, so for now we’re going to assume one could order and install the new-style vents. Instead of buying new pieces, you might want to glue the knee vents in place to prevent the knock-through and having them get chewed up by the drive shaft.
December 16, 2007
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.
December 16, 2007
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.
December 16, 2007
According to Polaris, the NGK BPR9ES and NGK BPR9EVX spark plugs are acceptable substitutes for the Champion RN57YCC and RN57YC spark plugs now found on Polaris engines. The NGK plugs seem to have better sealing gaskets that reduce seepage anytime the plugs have been removed and reinstalled. The ”EV” is a premium fine-wire electrode version of the “ES”.
Which brings to light another question, what is the difference between the Champion RN57YC and RN57YCC? According to Polaris, the RN57YC is also an acceptable replacement for the more commonly used RN57YCC, and that engine damage will not result from this substitution. The CC plug has a longer copper ground electrode for higher heat conductivity, with more coverage (longer ground electrode) for increased plug life, and reduced RFI (radio frequency interference). The CC plug is the better choice, but you can run the single-C version if needed.
It is also generally accepted to substitute the new NGK BR9ECS spark plug for all BR9ES applications. The ECS plug is now common issue on most if not all Ski-Doo two-strokes. This plug has a conical shape base which can allow for a shorter center electrode and a shorter ground electrode in comparison to the old standard BR9ES. The benefits of this are a reduction in pre-ignition and detonation by dissipating heat more efficiently via the electrode and conical shape base, along with a reduced chance of vibration breakage with the shorter ground electrode. And, they cost about twice what the BR9ES does.
The one substitution that is NOT recommended is to use the NGK BR9EYA in anything other than applications that specify this plug. This spark plug is primarily found in Arctic Cat two-stroke applications.
December 16, 2007
Yamaha has made available accessory rear heat exchangers for their 4-stroke models (all except Phazers). These accessory heat exchangers increase the cooling system capacity and are recommended for units that are operated in marginal snow conditions.
Each kit comes with mounting instructions, templates and required rivets. The kits are not covered under warranty, so the kit and installation costs are the responsibility of the sled owner, but Yamaha has made these kits available at a special reduced price to maximize owner satisfaction. The cost of the kit for 121†and 144†4-stroke models (8ET-RHECR-KT-00) is only $41.90, with the kit for 136†and 151†track lengths (#8EP-RHECR-KT-00) is only $85.29. See you Yamaha dealer for more details, to order a kit or have it installed.
December 16, 2007
There’s a good number of sleds out now that have the FOX FLOAT Airshox on the front suspension. While they have proven to be light and durable, they do require service and inspection.
One of the main benefits of this shock design is the ability to vary the airspring pressure with the use of a hand pump. The air pressure of each shock should be checked on a monthly basis through the winter. When you check the air pressure, you MUST do so with the front of the sled off the ground (the shock must be in an unloaded condition with no pressure being applied). Failure to unload the front suspension will lead to an incorrectly high pressure reading due to the shock being compressed.
Most of the FLOATs are shipped with 70 psi of air in them; their operating range is 50-150 psi. Changes should be made in 5 psi increments, with testing performed at each change to determine the result.
Remember that by attaching the air pump, it will take about 3-4 psi to fill the chamber in the pump and gauge so the shock will read this much lower than what it was really operating at. For example, you attach the pump and gauge to the shock and read 57 psi. This means you had about 60 psi in the shock to begin with.
If it was too soft (too much or frequent bottoming), pump it up to read 65 psi (you won’t lose any air when disconnecting the pump). If it was too firm (excessive harshness and suspension never bottoms out), reduce the pressure to read 55 psi (for the 5 psi change target) and try it.
It is best to set the shock air pressure at the temperature the unit will be operated at, or as close as possible. Ideally. If not, realize that a 50 degree change in temperature will change the air pressure by about 5 psi, and a 100 degree tremperature swing will amount to about a 10 psi swing in air pressure. If you set the shock to 60 psi in an 80 degree shop that the sled has been sitting in all day, it will be operating at about 50 psi when used at -20. Keep this in mind, the temperature swing can be enough to render your 5 psi change useless.
After each season, the outer air sleeve and seals should be cleaned. This service is safe for sled owners to perform, as long as they understand the high-pressure nature of the inner shock body and do not attempt to open it, or the pressure valve on the inner shock body. The internals of the shock should be rebuilt by a trained technician every 3,000 to 5,000 miles.
As for the air sleeve yearly service, a person of average mechanical ability should be able to handle it. No special tools are required, and detailed instructions to do so are included in the FLOAT owner’s manual (that comes with every sled so-equipped).
December 16, 2007
This one really had us scratching our heads for a while. One of our Ski-Doo 800s fitted with the PowerTEK engine package had a problem at the end of the year where the muffler would get really (and we mean REALLY) hot, so hot things started to melt. It would run good at about half throttle and above, but had difficulty idling. The check engine light came on and started flashing.
We first suspected the sled had gone into a timing retard mode, which built pipe heat, and after some steady running the heat got to the point that we could smell things getting hot. But, this wasn’t the case.
Instead, our Ski-Doo technicians discovered cracked carb intake boots, thus an air leak and a resulting lean condition. The sled was trying to compensate as much as it could, and did a great job, but the continued operation in this state led to the muffler getting extremely hot.
So, this episode reminded us of the importance of paying attention to your sled’s operation and maintenance. If you notice a sled running unusually hot and lean, the rubber carb intake boots have been known to crack on occasion. In this case it wasn’t a case of rot or deterioration as much as it was 3,000+ miles of cross-country pounding and a dose of bad luck. This particular sled was a 2006 MX Z 800 PTEK.
December 16, 2007
For almost ten years now, Yamaha snowmobiles have pretty much all been fitted with the hard and durable “8DN†drive belt. Performance tuners have found that while this drive belt is a fairly hard compound and seems to last forever, this firm nature also leads to a fair amount of slipping. And as you should be aware of, slipping creates heat, which is also lost acceleration. Bad deal.
Any way, the Yamaha mountain tuners at Hartman, Incorporated in Nampa, Idaho have long been recommending the use of the Dayco Ultimax 3 drive belt as a performance substitute, drive belt #138-4432-U3. This particular drive belt is made of a softer compound (more grip, less slip) and it is slightly longer, allowing you to set up the secondary to get the drive belt to the top of the sheaves, providing the full shift ratio and lowest possible start ratio (tougher to do with the shorter OE belt).
Hartman also believes the hard OE belts have been the cause of the sheave cracking they’ve seen on a number of Yamaha primary clutches, due to the heat generated from the hard belt slipping (and often sleds that are not properly calibrated for the operating conditions, also leading to an increase in belt slippage and heat generation).
Hartman has a truckload of these drive belts and sells them cheap – call them at 208-468-1073 or visit www.hartmaninc.com to get yours.
Newer Posts »
