Hey there

Hello, and welcome!

I'm actually rather new here myself, just been lurking for a while but your post caught my attention as I am also interested in building carbon fiber snowmobile parts.  I'll start by saying that I am still learning and definitely not an expert yet, so I'm not sure how much help I'll be able to offer, but I've been researching these things for a while, so maybe there will be something that can help you out. 

I am a little curious though, what is your skill level with composites parts/fabrication?  Also, just out of curiosity, what sled(s) are you working on? 

I've got a whole list of parts I'd like to build, but have been trying to start with simple things just to get the hang of it.  So far, I've only made a thin panel that will be used to help relocate the airbox on the throttle body, and a couple of small plates to replace the steel plates that originally sandwiched the steering shaft to the frame.  I had some excess resin and fabric left over when I made the thin panel for the airbox so I decided to make the other parts with it. 

A few more things on the list of future projects are:  Tunnel, float plate, body panels, headlight cover.  Obviously I want to have a good idea of what I'm doing by the time I get to the tunnel, so I've still got a ways to go. 

As far as how the composite rails for the rear suspension are made, I'm pretty sure Nextech is compression molding them, though I am not sure if they just add a little extra material in those areas and it gets pushed into place once inside the mold, etc.  It's also possible (though I'd think a lot less likely) that there is an excess of resin in those wider areas, making up part of the profile/shape. 

Depending on your experience with composites, I would most likely start out with smaller/flatter items, maybe some tunnel/running board reinforcements.  Another great starter project may be to just make some thin, flat panels to mount on the inside of the existing tunnel to help prevent snow from sticking.  Patrick Custom Carbon has some of these on their site, if I remember correctly.  Once you get to the point where you actually build the entire tunnel out of carbon fiber, you could still use the tunnel/running board reinforcement pieces to enhance the strength further, and the flat panels on the inside of the tunnel could be sold off with the tunnel (or separately).  That way you get to make some things (that are actually functional) while not getting too deep into the project. 

Hopefully this helps a bit in at least giving you a few ideas of which direction you'd like to start with first! 

I tried to upload a couple pics of the steering shaft plates I made.  I'm sure they only saved a small amount of weight, but most importantly, it allowed me to start learning more with minimal cost/risk.  If they don't work out, I just put the steel ones back on and chalk it up to a lesson learned!

Hey!  

Resin infusion would be a great technique for the simple body panels and maybe even the tunnel.

The suspension parts do look a bit like they have been compression moulded. If they have a good designed pair of moulds then the thicker pieces shouldn't be a problem for them to make with carbon rather than just a resin rich area.

They could be really clever and have lots of mould pieces all clamped together.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Looks to me like there is some sort of "filler/core" in the thick parts of the "runners"  Maybe they were made by layup over hard foam core or the like- 
A slightly softer core could be used (made very slightly oversize) in a compression mould or infusing two sides and "laminating" them together ..

"Sapere Aude"... Dare to KNOW!

The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind...

103% of all people do not understand statistics...

Do not adjust our mind, theres a fault in reality :-)

Well, Davajn, it sounds like you've got a great idea of what you want to do!

Yes, stronger and lighter is what I'm aiming for as well.  I am working with a 2007 Yamaha Phazer MTX.  If you're familiar with this machine, you probably already know it needs to be lightened a lot!  It's kind of funny actually, I'm doing pretty much the opposite of what you are.  My sled was a 144x14 wide track, and I'm stretching it to 155x15 wide.  Overall, the machine will only be about an inch (25.4mm) wider, but if I run out of other projects, I'd like to make some front suspension parts for it as well to narrow the ski stance a bit.  My background is mostly in precision machining, so that part of the project went pretty smooth, but now that I'm getting closer to needing the composite parts, I've been trying to do a lot more research.  It's amazing how much there is to know, and I find it both exciting and challenging to learn and attempt!

Your plan with the tunnel sounds like it should work pretty well!  I wish I could use formed aluminum for my tunnel mold, but ended up designing a new tunnel altogether (to allow mounting of a different rear suspension, etc.), so I am building the tooling plug entirely out of foam.  I do tend to feel like I have attempted a HUGE project for a beginner, but luckily I have a good friend (and fellow sledder) who works with composites every day, (doing fabrication and repair on large aircraft) who I can consult if I run into a problem. 

I am from Washington State in the USA, near Seattle.  As for the pictures, I think I added them as an attachment and did not embed them, so you may have to right-click and open them in a new window or download them by clicking on the link? 

Regarding the composite suspension rails pictured above, the company that makes them has a nice selection of photos on their site showing closer views, etc. as well as many of their other composite parts.  http://www.carbonsled.com/Photo_gallery.htm  Also, have you seen the Ski Doo 1200 turbo built by C3 powersports?  I just tried to link to their site, but it looks like it's down for maintenance.  Anyway, they had a lot of pictures and a nice video (may also be on youtube) showing a lot of their carbon fiber work, infusion, etc. 

Well I guess that's all for now, and I agree, it's nice to see another sledhead with a similar mindset!  It would obviously be easiest to just ride our sleds as they are, but for me, the building and modifying to the way I want it is half the fun...maybe even more!