Monthly Archives: December 2007

Rotax 600 Small-Block Twin Ring Replacement

Posted on by
Comments: Reply

Since Ski-Doo and Rotax have switched to a chrome-nitrated piston ring starting with the 2005 model year, older model year engines have been able to benefit from the later year rings. The chrome-nitrated rings improve reliability and reduce the possibility of flaking on the type 593 (600 small-block) engines, including HOs and SDIs.
The ring deterioration seems to be more common with pre-2005 Summit models, as the rings start to flake after a really good heat-soak that is more common with heavy loading of the engine and transmission in deeper, wet snows. Some lightly-used trail models can still have rings in decent shape with good compression yet, but if you own a pre-2005 Ski-Doo 600 small-block twin it wouldn’t be a bad idea to replace the rings and get all of the power you can from it. The old rings aren’t even available any more, new ones are now automatically sent instead.

 

2006 Yamaha Apex GT Primary Clutch

Posted on by
Comments: Reply

If you’ve got a 2006 Yamaha Apex GT, you’d better check the number stamped on the primary clutch. On the outer clutch cover, between one of the sets of tower bolts and center clutch bolt, you will find either the correct ID code of “8FP00” or you will find the incorrect code of “8FN00”. The code with the “P” means you have the correct primary clutch assembly for that exact model. If your clutch is stamped with the “N” code, then you have the wrong primary clutch. Take it to your nearest Yamaha dealer and get the right one installed.
Last year, Yamaha contacted all owners of record of these models to have this inspection performed, but a number of units could still remain unchecked.

 

2008 Polaris Dragon IQ

Posted on by
Comments: 3

When Polaris finds something that works, they expand upon it and run with it. Like their “Dragon” packages. Last year, the Dragon 700 was somewhat limited in availability, but nowhere short on performance and capability. The 700 CFI motor was getting all of the running quality issues worked out of it, as is typical with all-new fuel injection systems. Now, for 2008, the 700 CFI and the already-established 600 CFI are both ready for full-scale production.
We have been informed that the 800 CFI, which was planned to be introduced as a very late 2008 model in the form of an 800 Dragon, will be limited to the RMK models for 2008, with the 121” version released in January as a 2009 model. The demand for the limited number of these engines was too great from the mountain segment, where going to battle with an 800 is far more important than down at low elevation.
One of the issues with the 2007s was a hesitation when you wacked the throttle open quickly, or backed out of it abruptly. Polaris found the pressurized fuel rail in the EFI system needed to be “burped”, so they have added a “Fuel Vapor Separator” to all of the CFI engines to eliminate this problem. This was also added to all of the 2007s in the field that experienced this issue, as well.
Even with this update, the running quality of the CFI engine package continues to develop, much like the Ski-Doo SDI did in the first few years of production. Switching over from carbed engines to fuel injection isn’t as easy as one might think, and Polaris has done a great job at bringing their two-stroke engines up to where they needed to be after being sidetracked with the 755 and 866 big blocks for a couple of years. Now they’re back to what they do best; small block two-strokes, and now they’ll finally have a (125 HP) 600, (140 HP) 700 and (155 HP) 800.
What makes the Dragon models unique is their suspension packages, much like the Arctic Cat Sno Pros, Ski-Doo X-Packages and now the Yamaha RTXs. Compared to the base 700 IQ, the Dragons get a host of premium add-ons to increase their performance and value. The shocks are the most significant; new RydeFX Air 2.0 shocks up front get rid of steel springs, but use oil instead of air to seal the dual chamber. In the rear, an Air shock is on the front arm with a remote-reservoir compression adjustable RydeFX rear track shock. This is in contrast to the Walker Evans found on the Dragon 700 last season.
Other differences include a chrome windshield, painted spindles, a 1.25” Camoplast Ripsaw instead of a 1” Hacksaw, much taller handlebar risers (5.25” vs. 2.38”) and bar hooks with handguards (to go with the lower chrome windshield).
Polaris is really bent on making their sleds easy steering with a lighter effort, and once again they’ve reduced the steering effort with new spindles that are lighter as well. In fact, the whole sled is lighter with the use of their RAW Hybrid chassis that gets rid of as much weight as feasible. Most noticeable is the removal of the nose radiator, not needed with the small block engines. Instead, full-length tunnel extrusions do the job, complimented by a perimeter cooling system.
The rear suspension gets more tweaks for 2008 as well. Larger idlers are aimed at increasing top end speed. And, heavier standard torsion springs increase preload capability, either for aggressive riding styles or heavier riders, or both. Our big guys were always at the upper end of the previous spring capability, so this is a welcome change for all but the under 170-pound crowd.
You’ll also find a new Freestyle seat on the Dragons. This is narrow and firm in front, yet softer and wider in the back. Seems where you sit is a matter of how you are riding, and the dual-zone seat enhances rider mobility in the cockpit by making transitions easier, along with matching the foam density to the riding style. If you’re slid up front, then you’re riding aggressively and need a firmer seat, where if you’re back in the saddle you’re taking it easier and benefit from a more comfortable seat.
So, how does the Dragon IQ work in comparison to the rest of the class? Better than you’d maybe first expect. The IQ platform has never had any issues, short of the lacking performance of the big block engines of years past. The CFI 600 and CFI 700 deliver fuel economy that is right there with the Ski-Doo SDIs, maybe a whisker less, but better than the EFI Cats. The power is very strong for each engine size, with all three of them coming in at the top of their class.
The ride quality is very controlled, not as smooth or comfortable as the new F-Series Cats, but very capable and Polaris-like with excellent pitch control and weight transfer. No real issues, here, they bottom easier than the 2007 Ski-Doos but we’d have to say they’re better than the 2008 Ski-Doos in overall rear suspension performance.
The handling of the Dragons allows light steering and, if anything, isn’t aggressive enough for some. The Yamahas and Ski-Doos will carve with more precision, but with more effort as well. The Cats and the Dragons are really close in this regard, but again no real complaints other than we’d install different runners or skis as soon as possible. The stockers (skis and runners) are just not good enough for our liking.
The wind protection is typical for this class, racy-looking windshields sell sleds and make them faster, but when the temps drop below zero you start to feel it. We have a taller one on hand and swap them out, as needed. 200+ miles at -10 is no fun with a bikini windshield.
A valid gripe is the lack of storage on so many of the bump sleds, and this is true with the Dragons. There is a RAW look to the rear of the sled, where it is wide open wasted space. Ski-Doo used to nail this on their sleds, but now they’ve gone to the minimalist approach as well. If you want to carry gear, strap on a bag or get a backpack because there’s no on-board storage on the stock configuration. Polaris does have some cool (accessory) bags for this, now.
In reality, the Dragon models continue to be some of the most capable sleds in the widest range of conditions, a Polaris tradition. They are great trail sleds, not too firm like many others in this class, they steer easy and don’t wear you out. They are outstanding in deep snow for a 121” sled with 1.25” lug height. Polaris always does this better than anyone else. They are really light (476 dry spec for the 600) by all standards, except the new XPs. Polaris has worked like the dickens on product quality, and we’re confident these 2008s will be some of the best sleds they’re built in a number of years. Problem is, will their buyers recognize it, or is it too late? They should have had these sleds two-three years ago, but they’re here now. They are well-balanced in every respect, and other than the lack of storage and minimal wind protection, they will compared favorably in every regard. Maybe not the best at everything, but now they’re not bad at anything. And when the terrain gets really rough, they hold their composure and make you look and feel like a better rider. If you’re familiar with how well the 2007 Dragon 700 performed, get ready for more. More performance, more fun, more kicking your buddy’s butt all day long.
The 2008 Polaris Dragon IQ 600 retails for $9,499, and the Dragon IQ 700 goes for $9,899. The four-stroke Turbo Dragon sells for $10,249.

 

Rear Suspension Preload adjustments

Posted on by
Comments: Reply

Using the stock 22mm wrench to adjust the rear suspension preload on the Yamaha Phazer models is difficult. The wrench is short, and there isn’t much room up in the suspension to get the wrench to rotate through the cam adjustment. It’s a bugger.
So, we’ve gone back to an old trick from years past, the “speed wrench”. The easy way to make adjustments to your spring blocks, or cams, is to take a socket speed wrench with a 7/8” socket (most of us have one of these, very-very close to a 22mm) and you can flip the Phazer cam adjusters with amazing ease. This works far better to control the cam movement (as it comes past center) than a ratchet-socket combination, which allows the cam to slam into place due to the freewheeling ratchet action. A ratchet that allows you to “lock” it would prevent this from happening, and should work.
Generally, you want to rotate the block towards the open end of the spring, which would always be from the top of the cam towards the rear of the sled. Having an assistant unload the rear of the sled (take the weight off the springs) also makes it easier to rotate the cams. Make sure the socket is all the way onto the plastic adjusters, a slight misalignment can easily strip the edges of the plastic “nut” on the cam.
This technique works well on all brands of machines with cam adjusters, and allows you to do the job from the outside of the suspension without having to get your hands slammed around, or get your knuckles skinned. Leave the short wrenches for on-trail adjustments (and have your gloves on at all times when doing it the old-fashioned way).
And despite popular belief to the contrary, you do not have to have both sides set the same. The cams both apply their pressure to the same shaft, so you can set each cam individually to provide you with more possible settings. Instead of just low-low, medium-medium-medium and high-high, you can also set the blocks to low-medium and medium-high for five different settings instead of just three!
Ideally, the spring preload and cam settings should be selected to provide the proper ride height of the machine, or ride sag when the rider hops on. This generally is 30-40% of the suspension travel from a fully-extended position, and is simply a guideline. If the suspension is equipped with coupler blocks, you want to make sure the blocks are not yet engaged with the rider on the sled, or the ride quality will be in the “coupled” mode almost all the time. Generally, you want the couplers at a “mid-point” in the static (stationary) setting to provide an uncoupled (smoother) ride quality for the first portion of the suspension travel, and then crossing over to a firmer, more controlled ride when the blocks are engaged for the remainder of the suspension travel.

 

Parts For Pumps

Posted on by
Comments: 2

Dear Ralph:
I have a 1993 Polaris XLT. My problem is the water pump was leaking, so I removed it to check it out. The main seal was bad, so I called my Polaris dealer and he told me the only fix was to replace the entire pump assembly for about $300. Do you know where I can get the seal for this pump?
Dean Reid
Howell, MI

Many of the water pumps on snowmobilers are like this; if the seal goes bad you replace the entire pump. This is pretty common with many older sleds. In the case of the XLT, I believe the pulley is press fit onto the shaft and there really isn’t a viable service method for replacement of the seal. Many times you’ll find things like water pumps, oil pumps and even some fuel pumps where the unit is sold as an assembly and individual replacement parts are not available.
Many times the pump assembly is supplied by another vendor to the engine manufacturer. Other times the assembly of the pump is such that disassembly and reassembly will not meet certain specifications or tolerances. Think of it like a circuit board in your television; the problem may be a fifty-cent chip, but you’ll have to pay hundreds of dollars to replace the entire circuit board.

 

heavy stearing

Posted on by
Comments: Reply

Dear Ralph:
The steering seems really heavy on my sled. I mean the handlebars are hard to turn, and I really haven’t done much to it other than replace the wear bars. I’m afraid to change any of the settings because I don’t want to screw-up my new sled (it cost damn near $7000). The guys I ride with have all suggested things like cranking on the springs, but I was hoping you could give me some good old seat-of-the-pants recommendations. HELP!
Ron in Chicago

We edited out the make of Ron’s machine because this could be any brand of machine with this kind of problem. The first step would be to verify there is no binding or mechanical interference; lift and support the front of the sled off the ground and turn the handlebars through their entire range. They should pivot very freely. If not, locate and repair the mechanical interference.
Normally, on a stock machine that otherwise works very well, heavy steering (where excessive force is required to turn the handlebars) is normally caused by the skis. Wasn’t that profound? More accurately, it is caused by the skis either being too aggressive, they have too much carbide, or too much weight on them.
We’re assuming you haven’t installed new or different skis. If you have, there are so many possibilities. Usually, we’ll see a rider install a set of more aggressive skis and/or a more aggressive set of carbide runners when they want “better handling”, but they find it ends up being an animal to turn. When you replace the skis, or install a set of more aggressive runners, you have to be aware of all the other adjustments that could be needed to bring everything back into balance.
What adjustments? Things like the front ski springs, the limiter strap length, center shock spring and rear arm springs. Again, on an otherwise good working machine, you should try to stick to what it was that caused the heavy steering in the first place and work from that point forward. Let’s say you installed a new set of skis or runners and the steering is heavy. We could lighten the spring tension on the ski springs (less ski pressure), we could lengthen the limiter strap in the skid frame (less ski pressure), or we could soften the rear arm springs (again, less ski pressure). Which of these and in what quantity is the question. I prefer indexing my starting point (so I can always go back to it) and start with a little here and a little there. Most riders will use the ski spring pressure to compensate for worn runners (they’ll tighten them some to increase ski pressure), and the reverse works good for new runners that are a bit much for your liking.
For larger changes in ski pressure, you can change the length of the limiter strap(s) in the rear suspension. Making the strap(s) longer will reduce the amount of weight on the skis and reduce the steering effort. On coupled suspensions, I try to not vary the limiter more than one position so as to not change the moment of coupling. Increasing the center shock spring will have a similar, but lesser, affect in that it will reduce some of the ski pressure, and I’d personally see if this is enough before changing limiter strap length. These are the very adjustments the factory technicians spend so much time on getting right for each model and combination of tracks and skis, so when we start monkeying around with their track, ski, or runner selections then all of the adjustments might or might not be proper. Then again, much of it is more a matter of personal preference than being “right” or “wrong”.
The most overlooked adjustment that may surprise you is the rear suspension springs. Most riders will set these so they don’t bottom the rear, but if they’re a bit on the stiff side it will cause the steering to be heavy. A slight adjustment here may be all you need to bring it around.
Back to that new set of skis or runners; if this is what was installed to create the situation, you may want to consider a set of runners that isn’t as aggressive. Keeping in mind the need to balance the amount of traction with the amount of ski bite; if you’re running a large number of studs and need healthy runners to keep the front balanced with the rear, you may be hard pressed to find a runner length that will satisfy you.
When it comes to selecting carbide length, most riders seem to error on the long side and select runners with more carbide than they really need. Switching from a runner with 8” of carbide to one with 6” of carbide may be all it takes to get the results you want. I’ve seen it where we’ll bolt on a new set of runners and the first few days out our riders will complain about how heavy the steering has gotten. After hitting a few rocks and crossing a few asphalt roads, the edge of the runners is gone and the complaints usually go away.
You can always do some tweaking with your adjustments to get the type of handling you want. Remember that as conditions change, so will the amount of steering effort. You can change these adjustments from day to day if you’re really picky, but striking a balance that works well in most all conditions is the key for typical trail riders.
Other considerations would include the placement of the carbide in the wear bar and the amount of pressure being applied to the front and rear of the ski by the rubber damper that fits between the ski and the spindle. If there is too much carbide at the rear of the ski or if there is too much pressure towards the rear, it can also make the steering heavy, so you may want to verify the ski rubbers were installed properly. If you have a set of 8” runners and you’re looking to turn them into a set of 6” ones, take the extra carbide off the rear of the runner, not the front.

 

Mini-Z Headlight Failure

Posted on by
Comments: Reply

Pre-2007 Ski-Doo Mini-Z snowmobiles that burn out the headlight and/or tail light prematurely can now upgrade to the 2007 Mini-Z technology. Ski-Doo technicians have discovered some of the Honda engines used in the Mini-Z can produce a higher than expected AC output to the headlights.
Have your dealer order and install kit #515 176 489 (which is standard on 2007 Mini-Zs) to resolve this issue. It adds in parallel an additional load to the lighting circuit to ensure the voltage to the headlights and tail lamp does not exceed 14 volts.

 

Why Twin Spark Plugs?

Posted on by
Comments: Reply

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.