Service and Tuning Notes From the Jan/Feb 2006 Issue of Snowtech

New Ski-Doo Carbides
Most 2006 Ski-Doos come with new dual runner “Pilot” skis that are lighter, in part, thanks to new style square carbide runners with angled studs that are smaller (8mm) in diameter. This means that your current supply of carbide runners for the dual-runner Ski-Doo Precision skis will not fit the new Pilot skis found on the 2006 Ski-Doos. The new skis will provide improved handling with reduced steering effort, particularly more aggressive in heavy snow conditions.

M-Series & Crossfire Electric Start Kit
Arctic Cat now has an electric start kit available for the M-Series and Crossfire models. Order part #4639-275 for $529.95 US ($766.95 CDN). Available through any authorized Arctic Cat dealer.

Yamaha Apex & ATTAK Spark Plug Access
Lift the hood on a new 2006 fuel-injected Yamaha and you’ll soon notice you can’t quite gain easy access to the spark plugs. The Apex models’ rider-forward ergonomics design required some changes in component location, so to get at the spark plugs some additional bodywork and components need to be removed to gain access to the spark plugs. It looks intimidating at first, but by following this list it’s not all that bad.

1. Turn the two screws and remove the center shroud. These screws will stay in place within the shroud.

2. Remove the two self-tapping screws and chrome trim piece around the steering post.

3. Turn the four allen screws and remove the center dash panel (these allen screws will stay in place). The electrical connectors for the key switch and 12V accessory outlet need to be disconnected.

4. Remove two 6mm bolts and remove the headlight by moving it slightly to the rear, then up. The electrical connectors for the headlight and digital gauge will also need to be disconnected.

5. Remove one 6mm bolt that holds the smaller coolant tank in place, and move the tank to the side.

6. Remove the four bolts securing the plug caps. Each spark plug can be accessed using a swivel or flexible-type extension.

7. Reverse the procedure to reassemble.

Polaris Primary Spring Check
One of the most stressed parts in your sled is the primary clutch spring, and one of the most well-known springs to lose rate and cause your sled’s performance to fall off the map is the square-wire almond-black or the almond-red springs found in various Polaris models. These springs are very stressed in the primary clutch, and are most likely to exhibit a rate change that affects the shifting and performance of your sled.

Many tuners will carry an extra spring with them, especially when we’re talking about RMK models. The clutches can get really hot in extreme mountain riding, and this stress causes the rate of the spring to heat-sag. If your sled is equipped with one of these and is not running like it used to, try a new one and see what happens. Then carry a spare.

Polaris 600 H.O. Jetting
Speed shops are reporting the new Polaris 600 H.O. is indeed a very strong engine package, but that the engine requires a hot pipe to make full power and that the little mill is somewhat sensitive to the exact jetting. This engine varies ignition timing and power valve opening and is fitted with a detonation sensor, but it has no form of fuel delivery compensation or float bowl pressure control.

No surprise here, but with the automatic fuel delivery compensation systems of the others in this class, the need to be changing jetting is an area that can be improved upon for more accurate fuel delivery (and economy).

We do have options. The Holtzman ATACC float bowl pressure compensator system is being installed into these units by some of the speed shops to get the jetting more accurate. The ATACC automatically reduces the float bowl pressure as the temperature or elevation changes (similar to the Ski-Doo DPM), so the jetting and fuel delivery is more consistent with the engine’s requirements and the power delivery remains more consistent. If you experience flat performance due to jetting, consider one of these auto-compensation units from Holtzman Engineering (715-479-8727) to make it work even better as conditions vary.

Exhaust Springs Breaking?
Have you ever encountered a sled that starts to break exhaust springs, for no apparent reason? Quite often it is due to the exhaust system contacting the frame or chassis; look for compressed bump stoppers that allow the system to sit lower in the chassis, or compressed rubber pads that let the system shift. A change in exactly where the exhaust is positioned can allow contact with the chassis, and when this occurs you can see exhaust springs starting to break. Remove the exhaust system, inspect it and there you will find the point of contact, often with a shock tower, that allows the transmission of vibration and leads to springs breaking.

During the normal course of riding, exhaust springs can break with time and miles. This can be prevented by applying a dab of hi-temp silicone in between the coils to dampen any vibrations. Extra security of the junction can be had by installing a safety wire through the spring, so if it breaks the exhaust joint will continue to be held tight.

Also pay attention to the spring tension; the coils of the spring should just start to come apart in most locations. The spacing between the windings at the center of the spring should have .040” to .050” clearance between them when properly tensioned (can be measured with a feeler gauge). Too much tension can also lead to premature breaking. Often the metal tabs on the exhaust system (which the spring connects to) can be reformed to adjust the tension, using a tool like a locking pliers.

2003 Ski-Doo ZX Water Temp Warning Light
Do you have a 2003 Ski-Doo ZX model that likes to display the high water temp light? Maybe when it really doesn’t seem that hot? This was a problem with that vintage machine. The water temp warning light should come on at temps above 185 degrees F (85 degrees C).
To remedy the problem, have your dealer add a 68-ohm resistor to the coolant warning lamp circuit, per warranty bulletin 2003-9.

Polaris Big Block Hose Clamps
Owners of Polaris “big block” engines (700s, 800s and early 600s) should check the tension (tightness) of the hose clamp on the water pump on a regular basis. This particular clamp is known to loosen, and should be tensioned to 30-35 inch-pounds. To prevent it from loosening, you can bend the hose clamp “tail” over the head of the clamp screw for extra protection.

Also, do not ignore the condition of the water pump drive belt. This belt can and does deteriorate over time, and should be replaced when it reaches a width of 0.250” or if it is cracked or damaged (new belt width is 0.345”) . Polaris suggests this belt should be inspected at 1500-mile intervals.

2003-2004 Yamaha RX Mountain Tuning
Yamaha is suggesting the use of their clutching specifications for their 2005 RX-1 Mountain on all 2003 and 2004 model year RX-1 Mountain sleds. These earlier models have shown low shift RPM or a drop of shift RPM in some conditions and at some elevations.

The 2005 version featured a different calibration. Applying the 2005 specs to a 2003 or 2004 RX-1 Mountain will minimize the shift RPM loss at higher elevations. The recommendations, of course, are based on stock units with all other calibrations at Yamaha recommended settings. Refer to a 2005 (or 2006) Yamaha Technical Update manual to locate a 2005 RX-1 Mountain specification sheet for the new specifications.

C-36 Clicker Adjustments
2006 Ski-Doo MX Z and Renegade X packages fitted with the C-36 racing style shock absorber feature a high pressure piggy back design with both hi and low speed compression dampening adjusters. The low speed (shock shaft speed, not vehicle speed; think roller bumps, gullies) adjuster is in the center and has three full turns of adjustability. The high speed (shock shaft speed, not vehicle speed; think sharp edged bumps, fast compression hits) adjuster is the outer red nut (17mm) that allows for four full turns of adjustability.

Frozen Battery?
Batteries are now more common in snowmobiles, and many new models will not function properly if the battery is discharged. Keeping your snowmobile battery fully charged is also very important as the temperature drops, as batteries that are partially discharged can freeze, resulting in cell damage. For example, a battery that is only 50% charged can actually freeze at only zero degrees, and a battery that is 75% charged can freeze at –24º F.

Anytime the sled is going to be out of use for more than a month, the battery should be charged fully to keep it viable for as long as possible, and again on a monthly basis (minimum). Better yet, get one of the fancy automatic chargers (like the Optimate III or CTEK 3300 reviewed in the December SnowTech) that monitor the battery and switch to a low current maintenance charge for extended periods of storage.

2006 Ski-Doo 1000 SDI Oil Pump Cable
Ski-Doo has determined a limited number of 2006 models fitted with the 1000 SDI engine may have an incorrect oil pump cable adjustment. Machines with particular serial numbers should have this readjusted to prevent severe engine damage. Dealers should have notified all affected units to have this service performed, and they have the complete list of affected machines. This includes a limited number of 2006 Mach Z, Summit 1000 and Renegade X 1000s.

Cleaning Arctic Cat APV Exhaust Valves
Arctic Cat has provided us with a step-by-step procedure on cleaning the APV exhaust valves. These valves can become sticky and carbon up after many miles and hours of operation. Factors like type of oil used, operation conditions and driving habits can affect how often the valves need to be serviced.

Cleaning the carbon deposits from the exhaust valves ensures consistent performance and also improves fuel economy. As the valve is pulled up and down in the cylinder, it varies the height of the exhaust port and the port timing itself. Consistent positioning is achieved via a servo motor and cable. Keeping the valves clean ensures smooth movement and quick positioning.

Step 1: (The entire process is easier with the exhaust pipe removed.) Begin by removing the (opaque) plastic cover over the servo motor (where the cables from the valves run to).

Step 2: It’s critical to mark (index) which side of the servo pulley the cables attach to. Use a felt tip marker and you’ll eliminate guesswork during reassembly. Remove the black steel cable / housing retaining clip that holds the cables / housings in the servo retainer.

Step 3: Either rotate the servo slightly or pull the cable housing down to create slack in the cable. Slide the rear (closest to the fuel tank) cable end out of the motor, followed by the front cable. Then pull the cable / housing out from between the cylinders (It’s easiest to first remove the plastic retaining clip that holds both cables together).

Step 4: Working with one valve at a time, remove the two hex bolts that attach the valve assembly to the cylinder. Gently pull the valve out of the port, taking special note of how the guillotine-shaped valve was originally installed (on most engines, the long end of the valve faces up).

Step 5: Using a spray cleaner (brake cleaner, carb cleaner, oven cleaner) spray the guillotine valve, let it sit for a few moments, then use a wire brush to scrub away the rough carbon deposits on all sides of the valve (carefully select a brush and use care so you do not damage the valve).

Step 6: Reinstall the clean valve into the cylinder (we like to lightly lube it with injection oil beforehand), and repeat steps 4 & 5 with the other cylinder (s). When all valves have been cleaned and reinstalled, reroute the actuating cables to the servo. Perform the APV cable length measurement/adjustment outlined in your operator’s manual. Reinstall the cables into the servo (on the side you marked), reattach the plastic cable housing retaining clip, as well as the steel cable / housing retaining clip. Reattach the plastic servo cover and exhaust system.