Nytro Sled Prep '09

[arteeex]

The list below covers the most of what I’ve done to prepare my Nytro for this coming season. After I tore the sled apart one thing led to another and before I knew it, a little over 2-grand had been transformed in to sled parts, most of which was clearly unnecessary - according to my purchasing manager.

* A-arm bushings
* Powder coat rear suspension components
* Fully clip track
* Extrovert drivers
* Excel high-flow header
* Oil / filter
* Clean tunnel
* Replace loose rivets on tunnel and exhaust cover
* Replace slides
* Repair throttle heater
* Install tether switch
* Replace clutch side drive shaft bearing
* Replace drive shaft bolt
* Make and install stainless ski bolt bushings
* Replace 4 idler wheels
* Replace exhaust gaskets
* Ceramic coat header and flex joints
* Rebuild front shocks – upgrade to Float 2s
* Torsion spring spacers
* Simmons Gen 1 skis

Based on my experience with this tear-down, I suggest that anyone with 2500-miles or more on their sled dig in and check the clutch side drive shaft bearing, the bolt in the drive shaft (chain side) and exhaust gaskets. On my sled with 4600-miles the bearing was shot and the bolt going into the chain case side of the drive shaft was in two pieces. The exhaust gaskets between the flex joints and header were all but gone. I am replacing four idlers that are somewhat stiff to avoid downtime during the season. Loose rivets supporting a bracket on the exhaust shield under the seat and a few on the tunnel were replaced too. These loose rivets on the exhaust shield caused an annoying rattle/buzz at idle and when blipping the throttle. If you hear this, you know where to look first.

I went with the Float 2 rebuild thinking it was time to have the shocks serviced anyway. The report back from Fox was that even with 4600-miles on the shocks all the internals, seals and wipers were still in very good condition. So it seems, unless you’re looking to get more done or have an obvious problem, you can run the Floats substantially longer without rebuilding.

The powder and ceramic coatings (by Half Baked) was done to provide a little more life for the exhaust and to protect the corrosion prone bits under the sled. Really nice work by Half Baked too.

And, I’ll give a shout-out to Port Yamaha for their help, prices and prompt delivery – for which I will anticipate a large honorarium.

With a little more wrenching and a nice big dump of snow Angie and I will be ready to go.

 

[sleddingfarmer]

sounds alot like what I did a couple weeks ago. I started trying to figure how to get bigger idler wheels in my suspension so my slides would last longer...well I ended up accidently buying...

136" Cobra track, rail and tunnel extensions, 9T Avid drivers, 8 white slydog wheels, 4th wheel kit, yamaheater from rock, OFT Relocator, and 144 studs. Now I gotta instal all this stuff and probably find a bunch of stuff I'll need to replace...yay.

But I dont have a purchasing manager to answer too luckily

 

[SIKEWARD]

you guys need to do what I do tell the purchasing manager she can be fired and replaced! (she isn't reading this right?)

 

[towerrigger]

What about Jen? Is she the ugly step sister that gets no loving??

 

[arteeex]

Jen got a fully clipped track and will probably get a slightly taller riser too. She’s definitely lower maintenance and not as aggressive but still a blast to ride. I like her.

 

[Apex809]

I dont know if yamaha got a bad batch of bolts for the bottom chaincase bolt or not,but when i tried to remove mine it snapped in have. Could be something to check on. I didn't use much force at all and only had little over 500 miles on it. 08 MTX Nytro.

 

[woolyviper]

Jen got a fully clipped track and will probably get a slightly taller riser too. She’s definitely lower maintenance and not as aggressive but still a blast to ride. I like her.

so Jen is more like a girlfriend.....than a wife....

 

[arteeex]

The bolt I found broken in the drive shaft is only a problem for the models with reverse.

My guess is there's either repetitive side loading on this bolt leading to fatigue or it's self-tightening and breaking under tension. If it's common to have the bolt be intact but break when removing it, then the cause is more likely fatigue as this would cause a slow weakening of the material. I believe the part number of this bolt has changed since '08 so it may have been upgraded to reduce this issue.

I don't have any idea when the bolt failed on my sled and it didn't present any obvious symptoms.

 

[SledFreak]

If you are going to change the idlers, I would go with the DOO wheels. Better bearing, better wheels and will reduce the hyfax wear and reduce friction. Just mo..

 

[stopdropanroll]

The bolt I found broken in the drive shaft is only a problem for the models with reverse.

My guess is there's either repetitive side loading on this bolt leading to fatigue or it's self-tightening and breaking under tension. If it's common to have the bolt be intact but break when removing it, then the cause is more likely fatigue as this would cause a slow weakening of the material. I believe the part number of this bolt has changed since '08 so it may have been upgraded to reduce this issue.

I don't have any idea when the bolt failed on my sled and it didn't present any obvious symptoms.

When I took my chaincase apart I found the end of my bolt severed off deep inside the drive shaft, I guess the updated bolt doesn't do the trick, it was warrantied though.

 

[arteeex]

When I took my chaincase apart I found the end of my bolt severed off deep inside the drive shaft, I guess the updated bolt doesn't do the trick, it was warrantied though.

I don't get the bolt (technically, it's a screw) breaking where it is engaged with the treads of the drive shaft. On my sled the bolt snapped just below the end of the drive shaft but before the threads started. This is where you would expect a tensile failure to occur.

When the threads of the bolt and shaft are engaged there should be very little tensile force acting on the body of bolt. The threads are under shear near their root but this stress is going to be evenly distributed near the minor diameter over its length. I would suspect a problem in the material itself when you see breakage within the engaged threads.

 

[arteeex]

Here's this year's version of the exhaust shield, left side foot well block-off (an upgrade from duct tape) and stainless ski bolt bushings. The exhaust shield is similar but 12" longer to last year's model that worked well for me. For the foot well block-off I made patterns from construction paper and transferred these to a sheet of aluminum. I made the stainless ski bolt bushings because the stockers were rusted and nasty. In addition to powder coating the rear suspension, Half Baked also did the ceramic coating on the flex joints and header.

 

[BLUEBALLER]

Hey Steve-O,

I thought these Yammies were gas n go. What happened? LOL

 

[towerrigger]

I gotta ask you, How does your seat and exhaust plastic not melt with it covered right in. Will the ceramic coating cut the heat down that much?

P.S. I'll take 4 of those ski bushings. Made to length for a mountain ski. PM me for my address.

 

[arteeex]

Yeah, the gas and go thing is overrated. The babes wanna see the bling.

It's funny, in an odd way, how much time and money you can put into a toy that's pretty much disposable. But I know you're well aware of that too Blueballer, because I still have your list of SkiDoo tricks in my inbox.