Winter has arrived: Time to get the sled prepped

by • November 14, 2015 • UncategorizedComments (0)214

Alaska Snowrider file Learn how to care for your snowmachine now so when you’re in the field you can make repairs easier.

Alaska Snowrider file
Learn how to care for your snowmachine now so when you’re in the field you can make repairs easier.

By Michelle LaRose
Anchorage Snowmachine Club

We’ve not only seen the first snowfall this winter, but we actually got some accumulation in higher elevations. Here are some tips on prepping your ride, starting with purchasing your sleds’ operations manual beforehand (if you lost it, or never had one) and making sure you follow the manufacters’ protocol.

Let’s begin with fluids
We’re talking gear lubes in chaincases and coolant in liquid-cooled sleds. The fluids don’t wear out; they become contaminated by water and debris, including condensation from rapid temperature changes and atmospheric moisture. Change you chaincase gear oil every pre-season. Dust and water inhaled through the chaincase breather along with inevitable microscopic bits of gear-metal in the chaincase contaminate the gear oil over a riding season. It’s important to remove the chaincase cover per the manual instructions because you want to let debris flow out that settle at the bottom, wiping the rest out. Suction devices do not remove that debris. When it comes time to reinstall the cover, tighten the cover bolts in a cross-pattern fashion not to deform the casting, work gradually from bolt to bolt.

As for coolant (liquid-cooled engine), there is a specific type of coolant your machine requires. Did you know “the green stuff” can harm some RV water pump seals? It contains a polymer silicates–microscopic chemical ball-bearings, specifically designed for thicker automotive water pump seals. Silicates can destroy some smaller RV water pump seals over time, necessitating removal and replacement of the water pump. The “red coolant” known as Dextron, is made for the aluminum and brass parts of a radiator and does NOT contain silicates. DO NOT mix the two types of coolants. Drain the cooling system of debris and dirt every other riding season. Consult your manual but often it’s required to disconnect a hose end or two and elevate the rear of the sled to remove all of the old coolant. When it comes to refilling the cooling system, you usually have to raise the front of the sled to let the coolant drain to the rear of the ride while the engine is running the water pump. This is important as air pockets in the coolant reduce cooling efficiency and can cause overheating.

Don’t overlook flushing the brake fluid. DOT3 brake fluid is hygroscopic; it absorbs moisture out of the atmosphere, which snowmachines have plenty of. Water in brake fluid corrodes parts in the brake system over time. It’s as simple as a $5 pint of new brake fluid. Remove the master cylinder reservoir cover near the brake handle then attach a section of clear vinyl hardware store hose to the bleeder screw down on the caliper and aim into a bottle. Use the proper size open wrench and carefully open the bleeder screw ever so slightly, just enough to let fluid seep through the transparent hose as you pull the brake handle slowly forcing old fluid out. Hold the brake handle all the way in while turn the bleeder screw clockwise to close just snug. Let the handle extend slowly back to rest position once the bleeder screw is closed-do not let up on the brake handle when the bleeder screw is open because you’ll draw air. Add new fluid as needed to keep the master cylinder from going dry after each pump. Repeat these procedures until you get mostly clear fluid in the hose. Don’t overtighten the bleeder screw when finished. Be sure a rubber or vinyl cap is over the end of the bleeder screw so water can’t run down the bleeder hole and corrode the bleeder-screw threads making the next removal tricky.

Now onto the exhaust valves
The exhaust valves of a two-cycle engine should be cleaned at the outset of every season for engine breathing efficiency.  Have your service manual handy on this one, especially if you haven’t done it before. Cleaning the exhaust valves starts with new gaskets or o-rings, don’t reuse old gaskets or O-rings because this can cause crankcase vacuum/pressure leaks resulting in engine power loss that is hard to track down. Gaskets or o-rings usually have to be ordered in advance.

Have a camera ready to take some photos of the engine compartment or draw diagrams because when you remove the exhaust valves, you’re going to need to remember where hoses and wires go. If prior cleaning of the exhaust valves has been neglected in the past, they can be stuck in their bore with carbon buildup making removal difficult. If it seems impossible to remove the reed valves, do not pry them out. Consult a mechanic. Most often the whole valve assembly will slide out, but watch for falling parts.  The safest way to remove baked-on carbon is with fine-grade scotchbrite pad and lacquer thinner carefully not to make deep gouges in anything. Some people use spray-on oven cleaners to remove baked carbon. Wipe clean, then consult the manual for reassembly. (Tip: Look for oil inside the bellows indicating exhaust stem seal failure which causes premature carbon buildup on the valve assembly).

How many of you know that a snowmachine track has a need for alignment relative to the track runners and even the skis? All skis are adjustable in-and-out, they often become misaligned due to bumping into objects along the trail, but the track itself is also adjustable relative in alignment to the chassis rails it rides on.
What you must do to check the track alignment is to elevate the rearend of the sled safely. Then slowly rotating the rubber track by hand (while you’re at it, inspect for gouges & missing lugs in the track), notice how the side-to-side spacing of the track clips relative to the hyfax and the chassis rails. Should be the same on either side.  Look at the hyfax, the long plastic-like nylon/telfon runner that the rubber track rides against, for cracking or thin spots at the bottom especially near the front of the rails.

Consult your service manual for methods of adjustment or replacement of parts. Most often, rubber track tension adjustment is a matter of loosening the tracks’ rearmost idler wheels and sliding them along a channel independently to affect an alignment change, then retighten to specified clamping force. It’s critical to the longevity and efficiency of the machine. Too tight and parts wear out prematurely and sap horsepower from the unnecessary friction. Too loose you sacrifice engine efficiency through track “whip” and run the risk of the track banging the top of the track tunnel and damaging the radiator in the tunnel. Check your track. Proper tension is provided in your service manual, but 99 percent of the time, you should just be able to pull the track down at the bottom at midpoint, and at about an inch of slack then you should feel serious resistance to pulling it down any farther. Specific measurement is typically about 16 pounds of force to pull it down with a fish-scale while measuring 1.25-1.50 inches distance from the bottom of the rail or hyfax to the topside of the rubber track.

There’s much more than can be covered, like checking the tightness of the header exhaust pipe to the cylinder head, greasing zerks to force water out of the pivot points, spark plug cleaning and gapping, chaincase chain tension, oil tank filter replacement. Consult the service manual specific to your sled.

Proper tightening torques are in there, which keep you from stripping out threads, cracking casting covers and ruining gaskets.

And the best part of all this? If you break down out in the middle of nowhere and have at least the basic tools, you have familiarized yourself enough with the parts and how they work together so you can prevent spending a night out in the cold.

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