Mothballing the Nytro Snowmobile

Post by blogger | June 26, 2008      

If there is any way to say ‘by to the ski season, it’s when we remove a section of fence, drive our Yamaha Nytro through the yard, and park it for the summer. Since we now own a high end sled instead of a beater, we took the time to make a weed resistant flagstone “sled patio” next to our backyard storage shed, where it’s shaded most of the afternoon and away from prying eyes. We covered the sled with our factory cover, then with a poly tarp.

Colorado backcountry skiing and snowmobiling.
The mothballing process is important when you’re storing expensive machinery. First, we mixed some Stabil gasoline preservative into the tank, and ran it through the engine for a few minutes. After that, we tied screen wire over the exhaust so critters wouldn’t take up residence. I thought we’d need to do the same for the intake, but after getting frustrated by air intakes we couldn’t reach in the cramped engine compartment, we realized that the air filter has a wire mesh layer that’ll prevent any mice from gnawing their way into the intake manifold. Lastly for the mechanicals, we disconnected the battery.

Perhaps our worst problem is neighborhood cats spraying what looks important to them (tarps over stuff seem to fit that criteria). I’ve had good luck using mothballs to keep cats at bay, so we spread a whole box of the toxic little buggers on and around the sled. More, I got a bottle of “animal repellent” from the hardware store, and gave the snowmobile seat and cover a good hit with that as well. (Note to self, try the hardware store stuff for Marmots that gnaw on our Jeep).

Yamaha Nytro: Thoughts after One Season

How about a short gear review of the Nytro, after we abused it for a few months?

Overall we’re happy with the sled. It’s got the power necessary for towing skiers or a cargo sled, and it’s most certainly fun to drive when you leave the skis behind and go joy riding.

Using the Nytro as a work snowmobile has its problems, however. Worst is that the performance stance and suspension of the Nytro make it super tippy. Even with the skis set to widest, the machine ends up on its side with little more than a weight shift and tweak of the steering. That kind of sensitivity is what sport riders want, but when you’re tired and just trying to get across a sidehill to your ski destination, squirrel action is not appreciated. Solution is suspension tweaking. We tightened the coilover springs on the ski shocks and got good results, but I’m thinking the complete suspension needs to be adjusted so the whole sled sits a few inches lower. We’ll be trying that next fall.

Perhaps more importantly than handling issues, the Nytro engine overheats much too easily. Cause is an undersized heat exchanger that’s mounted up front in the tunnel, where it gets less snow thrown on it than those mounted to the rear of the tunnel. Performance sled mechanic told me the solution is to plumb in a sister heat exchanger. Major PITA, but probably necessary. Along with that, mechanic told me we should move our muffler and tail exhaust down into the tunnel where it belongs, so we can use our cargo area without melting our gear (we insulated our exhaust extension, but it still gets fairly hot). Sounds good to me, so we’ll see what autumn brings for snowmobile mods. After all, nothing at WildSnow shall remain unmodified!


9 Responses to “Mothballing the Nytro Snowmobile”

  1. John Gloor June 26th, 2008 4:16 pm

    As you know Lou, high performance powder sleds pulling skiers on hard trails often leads to overheating. I recently added ice scratchers to my RMK 800 and it helped some. I am thinking of adding a Van Amburg heat exchanger but they are pricey ($479). I think they make Yamaha parts also. Thanks for the sled updates this last season. I used your ideas and pictures to fashion a similar rack. I would never have thought of using snowboard bindings. The setup is far superior to the vertical tubes on the sled I gave a friend.

  2. Lou June 26th, 2008 4:37 pm

    Yeah John, we did the ice scratchers and they really helped, just not quite enough, especially on pavement (grin). We got some ski wheels as well, but they only work for moving the sled in and out of the garage. One time on Maroon Creek Road, I rigged up a sun shower with a tube dripping water on the heat exchanger. That worked, but is big and heavy if you bring enough water to make a difference. At least you can take a shower after a few hours of sledding (g).

  3. adam olson June 27th, 2008 7:51 am

    “Along with that, mechanic told me we should move our muffler and tail exhaust down into the tunnel where it belongs”

    Did he say to run the whole exhaust pipe through and out the tunnel or just dump exhaust into the tunnel?


  4. Lou June 27th, 2008 8:41 am

    Adam, he said there was a way to get everything down in the tunnel, with the exhaust exiting out the rear. It would be easy to spray the exhaust into the tunnel, but then you’d be in a cloud of exhaust unless you were moving (like the old days).

  5. Lou June 27th, 2008 9:55 am

    I just spoke with the snowmobile mech, he said I should probably prop up the rear of the sled so the suspension is unloaded and possibly lifting the track off the ground. He also said to place some Decon in there as well as the other chemistry. Anything but having your wiring harness eaten, or a rat nesting in your air filter box.

  6. Ken June 27th, 2008 10:00 am

    Lou – Something to remember is that UV rays do bad things to plastic with increased exposure. I’d suggest covering your skis as well…if not, at least give them a healthy coat of 303 protectant for the season. Unless, of course, you’re looking for a good reason to upgrade to some Generation II Simmons flexi-skis for next season! -Ken

  7. Lou June 27th, 2008 10:12 am

    he he, always looking for an upgrade! But yeah, we were talking about covering up the skis, so I think we’ll do that too. Man, I wish we just had a garage for this thing. I was keeping it in the garage during the winter, but need the room for automotive projects in the summer.

  8. Jim Jones June 28th, 2008 8:12 am

    I’m on my 8th sled of my life and have never, ever, had a problem with over-heating. I began pulling skiers behind my sleds in the early 80’s so yes, I have abused them.

    I guess its time to build another garage.

  9. John Gloor June 28th, 2008 11:36 am

    Jim, what type of sleds are you running? My Arctic cat 580 never overheated once but my RMK 800 is good for two miles on frozen spring roads before it goes into its limp mode when hot. I”ve bled the system of all air but the problem is no snow on the heat exchangers. I don’t want to go the touring or work sled route since they weigh a ton and are not as fun. They are probably better suited for towing though.

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Welcome to Louis (Lou) Dawson's backcountry skiing information & opinion website. Lou's passion for the past 50 years has been alpinism, climbing, mountaineering and skiing -- along with all manner of outdoor recreation. He has authored numerous books and articles about ski touring and is well known as the first person to ski down all 54 of Colorado's 14,000-foot peaks, otherwise known as the Fourteeners! Books and free ski touring news and information here.

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